two points and an equation
So I think this is the question, I forget how its worded exactly, so bear with me. Suppose we have an equation $5x^3 + bx^2 + cx + d$ cirve that passes through the points $(0,0)$ and $(2,0)$ and the question asks me to solve for $b$ in the equation. How do I do it?
graphing-functions problem-solving
New contributor
add a comment |
So I think this is the question, I forget how its worded exactly, so bear with me. Suppose we have an equation $5x^3 + bx^2 + cx + d$ cirve that passes through the points $(0,0)$ and $(2,0)$ and the question asks me to solve for $b$ in the equation. How do I do it?
graphing-functions problem-solving
New contributor
1
Welcome to Maths SX! You only can have a relation between $b$ and $c$.
– Bernard
Jan 4 at 21:11
1
Did you try putting both points into the equation and seeing what you get? (I suppose it's an equation $y=...$, yours isn't an equation, it doesn't equate anything)
– orion
Jan 4 at 21:13
add a comment |
So I think this is the question, I forget how its worded exactly, so bear with me. Suppose we have an equation $5x^3 + bx^2 + cx + d$ cirve that passes through the points $(0,0)$ and $(2,0)$ and the question asks me to solve for $b$ in the equation. How do I do it?
graphing-functions problem-solving
New contributor
So I think this is the question, I forget how its worded exactly, so bear with me. Suppose we have an equation $5x^3 + bx^2 + cx + d$ cirve that passes through the points $(0,0)$ and $(2,0)$ and the question asks me to solve for $b$ in the equation. How do I do it?
graphing-functions problem-solving
graphing-functions problem-solving
New contributor
New contributor
edited Jan 4 at 21:21
amWhy
192k28225439
192k28225439
New contributor
asked Jan 4 at 21:08
Ryan smithRyan smith
4
4
New contributor
New contributor
1
Welcome to Maths SX! You only can have a relation between $b$ and $c$.
– Bernard
Jan 4 at 21:11
1
Did you try putting both points into the equation and seeing what you get? (I suppose it's an equation $y=...$, yours isn't an equation, it doesn't equate anything)
– orion
Jan 4 at 21:13
add a comment |
1
Welcome to Maths SX! You only can have a relation between $b$ and $c$.
– Bernard
Jan 4 at 21:11
1
Did you try putting both points into the equation and seeing what you get? (I suppose it's an equation $y=...$, yours isn't an equation, it doesn't equate anything)
– orion
Jan 4 at 21:13
1
1
Welcome to Maths SX! You only can have a relation between $b$ and $c$.
– Bernard
Jan 4 at 21:11
Welcome to Maths SX! You only can have a relation between $b$ and $c$.
– Bernard
Jan 4 at 21:11
1
1
Did you try putting both points into the equation and seeing what you get? (I suppose it's an equation $y=...$, yours isn't an equation, it doesn't equate anything)
– orion
Jan 4 at 21:13
Did you try putting both points into the equation and seeing what you get? (I suppose it's an equation $y=...$, yours isn't an equation, it doesn't equate anything)
– orion
Jan 4 at 21:13
add a comment |
2 Answers
2
active
oldest
votes
You don't have enough information for a unique solution
What you can do is:
$y = 5x^3 + bx^2+ cx + d$
Plug 0 in for x and 0 for y.
$d = 0$
Then plug 2 in for x and 0 for y
$40 + 4b + 2c = 0$
$b = -10 - frac 12 c$
And that is as far as you can go.
add a comment |
For the point $(0, 0)$, you get
$$0 = 5(0)^3+b(0)^2+c(0)+d iff d = 0$$
So the equation is essentially $f(x) = 5x^3+bx^2+cx$.
For the point $(2, 0)$, you get
$$0 = 5(2)^3+b(2)^2+c(2) iff 0 = 40+4b+2c iff -40 = 4b+2c iff -20 = 2b+c$$
There isn’t enough information to solve for $b$. However, you can come up with a relation between $b$ and $c$, as shown.
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
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votes
You don't have enough information for a unique solution
What you can do is:
$y = 5x^3 + bx^2+ cx + d$
Plug 0 in for x and 0 for y.
$d = 0$
Then plug 2 in for x and 0 for y
$40 + 4b + 2c = 0$
$b = -10 - frac 12 c$
And that is as far as you can go.
add a comment |
You don't have enough information for a unique solution
What you can do is:
$y = 5x^3 + bx^2+ cx + d$
Plug 0 in for x and 0 for y.
$d = 0$
Then plug 2 in for x and 0 for y
$40 + 4b + 2c = 0$
$b = -10 - frac 12 c$
And that is as far as you can go.
add a comment |
You don't have enough information for a unique solution
What you can do is:
$y = 5x^3 + bx^2+ cx + d$
Plug 0 in for x and 0 for y.
$d = 0$
Then plug 2 in for x and 0 for y
$40 + 4b + 2c = 0$
$b = -10 - frac 12 c$
And that is as far as you can go.
You don't have enough information for a unique solution
What you can do is:
$y = 5x^3 + bx^2+ cx + d$
Plug 0 in for x and 0 for y.
$d = 0$
Then plug 2 in for x and 0 for y
$40 + 4b + 2c = 0$
$b = -10 - frac 12 c$
And that is as far as you can go.
answered Jan 4 at 21:15
Doug MDoug M
44.2k31854
44.2k31854
add a comment |
add a comment |
For the point $(0, 0)$, you get
$$0 = 5(0)^3+b(0)^2+c(0)+d iff d = 0$$
So the equation is essentially $f(x) = 5x^3+bx^2+cx$.
For the point $(2, 0)$, you get
$$0 = 5(2)^3+b(2)^2+c(2) iff 0 = 40+4b+2c iff -40 = 4b+2c iff -20 = 2b+c$$
There isn’t enough information to solve for $b$. However, you can come up with a relation between $b$ and $c$, as shown.
add a comment |
For the point $(0, 0)$, you get
$$0 = 5(0)^3+b(0)^2+c(0)+d iff d = 0$$
So the equation is essentially $f(x) = 5x^3+bx^2+cx$.
For the point $(2, 0)$, you get
$$0 = 5(2)^3+b(2)^2+c(2) iff 0 = 40+4b+2c iff -40 = 4b+2c iff -20 = 2b+c$$
There isn’t enough information to solve for $b$. However, you can come up with a relation between $b$ and $c$, as shown.
add a comment |
For the point $(0, 0)$, you get
$$0 = 5(0)^3+b(0)^2+c(0)+d iff d = 0$$
So the equation is essentially $f(x) = 5x^3+bx^2+cx$.
For the point $(2, 0)$, you get
$$0 = 5(2)^3+b(2)^2+c(2) iff 0 = 40+4b+2c iff -40 = 4b+2c iff -20 = 2b+c$$
There isn’t enough information to solve for $b$. However, you can come up with a relation between $b$ and $c$, as shown.
For the point $(0, 0)$, you get
$$0 = 5(0)^3+b(0)^2+c(0)+d iff d = 0$$
So the equation is essentially $f(x) = 5x^3+bx^2+cx$.
For the point $(2, 0)$, you get
$$0 = 5(2)^3+b(2)^2+c(2) iff 0 = 40+4b+2c iff -40 = 4b+2c iff -20 = 2b+c$$
There isn’t enough information to solve for $b$. However, you can come up with a relation between $b$ and $c$, as shown.
answered Jan 4 at 21:16
KM101KM101
5,8611423
5,8611423
add a comment |
add a comment |
Ryan smith is a new contributor. Be nice, and check out our Code of Conduct.
Ryan smith is a new contributor. Be nice, and check out our Code of Conduct.
Ryan smith is a new contributor. Be nice, and check out our Code of Conduct.
Ryan smith is a new contributor. Be nice, and check out our Code of Conduct.
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1
Welcome to Maths SX! You only can have a relation between $b$ and $c$.
– Bernard
Jan 4 at 21:11
1
Did you try putting both points into the equation and seeing what you get? (I suppose it's an equation $y=...$, yours isn't an equation, it doesn't equate anything)
– orion
Jan 4 at 21:13