Factor a^2-a-90

Problem

a2−a−90

Solution

1. Identify the coefficients of the quadratic expression in the form a*x2+b*x+c where a=1 b=−1 and c=−90

2. Find two numbers that multiply to the constant term c=−90 and add to the linear coefficient b=−1

3. Determine the factors of −90 that satisfy these conditions, which are −10 and 9 because (−10)×9=−90 and −10+9=−1

4. Write the expression in factored form (a+p)*(a+q) using the numbers found.

Final Answer

a2−a−90=(a−10)*(a+9)

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