SOLUTION: How do I solve the quadratic equation 36x squared minus 25=0? I tried using the quadratic formula and factoring, but can't get an answer that's right.

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Question 982217: How do I solve the quadratic equation 36x squared minus 25=0? I tried using the quadratic formula and factoring, but can't get an answer that's right.
Answer by macston(5194) About Me  (Show Source):
You can put this solution on YOUR website!
.
Difference of two squares:
36x%5E2-25=0
Take square root of 1st term plus square root of 2nd term:
6x+5
Multiply by square root of 1st term minus square root of 2nd term:
%286x%2B5%29%286x-5%29=0
6x%2B5=0 or 6x-5=0
6x=-5 or 6x=5
x=-%285%2F6%29 or 6=5%2F6
x=plus or minus (0.8333)
.
However, the quadratic formula does work:
Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation ax%5E2%2Bbx%2Bc=0 (in our case 36x%5E2%2B0x%2B-25+=+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=%280%29%5E2-4%2A36%2A-25=3600.

Discriminant d=3600 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28-0%2B-sqrt%28+3600+%29%29%2F2%5Ca.

x%5B1%5D+=+%28-%280%29%2Bsqrt%28+3600+%29%29%2F2%5C36+=+0.833333333333333
x%5B2%5D+=+%28-%280%29-sqrt%28+3600+%29%29%2F2%5C36+=+-0.833333333333333

Quadratic expression 36x%5E2%2B0x%2B-25 can be factored:
36x%5E2%2B0x%2B-25+=+36%28x-0.833333333333333%29%2A%28x--0.833333333333333%29
Again, the answer is: 0.833333333333333, -0.833333333333333. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+36%2Ax%5E2%2B0%2Ax%2B-25+%29