SOLUTION: Use the quadratic formula to solve the following equations x^2 + 7x + 6 = 0

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Question 101014: Use the quadratic formula to solve the following equations
x^2 + 7x + 6 = 0
Answer by doukungfoo(195) About Me  (Show Source):
You can put this solution on YOUR website!
First here is the quadratic formula:
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
The standard form of a quadratic equation is
ax%5E2%2Bbx%2Bc=0
So we are going to use the quadratic formula to solve
x%5E2%2B7x%2B6=0
a in our problem is 1
b in our problem is 7
c in our problem is 6
so first fill in these numbers for a, b, and c
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
x+=+%28-7+%2B-+sqrt%28+7%5E2-4%2A1%2A6+%29%29%2F%282%2A1%29+
x+=+%28-7+%2B-+sqrt%28+49-24+%29%29%2F2+
x+=+%28-7+%2B-+sqrt%28+25+%29%29%2F2+
at this point lets split the equations in to two seperate equations
we are doing this because of the +- in front of the square root
so now we have this:
x=+%28-7%2Bsqrt%2825%29%29%2F2 AND x=+%28-7-sqrt%2825%29%29%2F2
x=+%28-7%2B5%29%2F2 AND x=+%28-7-5%29%2F2
x=+-2%2F2 AND x=+%28-12%29%2F2
x=+-1 AND x=+-6
So the solutions for x are -1 AND -6
check both in the original equation
x%5E2%2B7x%2B6=0
%28-1%29%5E2%2B7%28-1%29%2B6=0
1-7%2B6=0
0=0
----------------------
x%5E2%2B7x%2B6=0
%28-6%29%5E2%2B7%28-6%29%2B6=0
36-42%2B6=0
0=0

The both work so we can be sure we have solved the equation correctly.