SOLUTION: The math problem says solve for 'X' 5x^2-3x=1 i had to subract from both sides 5x^2-3x-1=1-1 5x^2-3x-1=0 it says i have to apply the quadratic formula. Once i plugged my

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Question 292613: The math problem says solve for 'X'
5x^2-3x=1
i had to subract from both sides
5x^2-3x-1=1-1
5x^2-3x-1=0
it says i have to apply the quadratic formula. Once i plugged my numbers in for -4AC it says its wrong.. how do i plugg them in ? so i can finnish solivng the rest of the equation.
Found 2 solutions by richwmiller, Edwin McCravy:
Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
not just 4ac but the whole quadratic formula.
Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation ax%5E2%2Bbx%2Bc=0 (in our case 5x%5E2%2B-3x%2B-1+=+0) has the following solutons:

x%5B12%5D+=+%28b%2B-sqrt%28+b%5E2-4ac+%29%29%2F2%5Ca

For these solutions to exist, the discriminant b%5E2-4ac should not be a negative number.

First, we need to compute the discriminant b%5E2-4ac: b%5E2-4ac=%28-3%29%5E2-4%2A5%2A-1=29.

Discriminant d=29 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28--3%2B-sqrt%28+29+%29%29%2F2%5Ca.

x%5B1%5D+=+%28-%28-3%29%2Bsqrt%28+29+%29%29%2F2%5C5+=+0.83851648071345
x%5B2%5D+=+%28-%28-3%29-sqrt%28+29+%29%29%2F2%5C5+=+-0.23851648071345

Quadratic expression 5x%5E2%2B-3x%2B-1 can be factored:
5x%5E2%2B-3x%2B-1+=+5%28x-0.83851648071345%29%2A%28x--0.23851648071345%29
Again, the answer is: 0.83851648071345, -0.23851648071345. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+5%2Ax%5E2%2B-3%2Ax%2B-1+%29

Answer by Edwin McCravy(20054) About Me  (Show Source):
You can put this solution on YOUR website!

When you get here:

5x%5E2-3x-1=0

Compare that to

ax%5E2%2Bbx%2Bc=0

and you can see that a=5, %22%22%2Bb=-3 and %22%22%2Bc=-1

Then you write

x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+

Now substitute %285%29 for a, %28-3%29 for b, and %28-1%29 for c
in that equation, and when you do you get:



Then you simplify that:

x+=+%283+%2B-+sqrt%289%2B20+%29%29%2F10+

x+=+%283+%2B-+sqrt%2829+%29%29%2F10+

So you have two solutions.

Solution 1 has a + where the ± is

x+=+%283+%2B+sqrt%2829%29%29%2F10+
Then use your calculator to get the approximation for solution 1:
 
 
Solution 2 has a - where the ± is

x+=+%283+-+sqrt%2829%29%29%2F10+
Then use your calculator to get the approximation for solution 2:


Edwin