SOLUTION: How would you find x on an isoceles triangle if the base is 9, and the two congruent sides are 5x^2+9x-10 and 4x^2+5x+11

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Question 666659: How would you find x on an isoceles triangle if the base is 9, and the two congruent sides are 5x^2+9x-10 and 4x^2+5x+11
Answer by MathLover1(20855) About Me  (Show Source):
You can put this solution on YOUR website!
the two congruent sides are 5x%5E2%2B9x-10 and 4x%5E2%2B5x%2B11;
so if two sides congruent, we have
5x%5E2%2B9x-10=4x%5E2%2B5x%2B11....solve for x

5x%5E2-4x%5E2%2B9x-5x-10-11=0
x%5E2%2B4x-21=0.....use quadratic formula
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
x+=+%28-4+%2B-+sqrt%28+4%5E2-4%2A1%2A%28-21%29+%29%29%2F%282%2A1%29+
x+=+%28-4+%2B-+sqrt%28+16%2B84+%29%29%2F2+
x+=+%28-4+%2B-+sqrt%28100%29%29%2F2+
x+=+%28-4+%2B-+10%29%2F2+.....since side has to be positive, we will look for positive root only
x+=+%28-4+%2B+10%29%2F2+
x+=+6%2F2+
highlight%28x+=+3%29+