Factor x^2+x-72

Problem

x2+x−72

Solution

1. Identify the coefficients of the quadratic expression in the form a*x2+b*x+c where a=1 b=1 and c=−72

2. Find two numbers that multiply to c (which is −72 and add to b (which is 1.

3. Determine the factors by testing pairs of numbers that multiply to −72 such as 9 and −8

4. Verify that 9 + (-8) = 1a*n*d \cdot (-8) = -72$.

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

Final Answer

x2+x−72=(x+9)*(x−8)

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