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 8 and −9

4. Verify the sum: 8 + (-9) = -1,w*h*i*c*h*m*a*t*c*h*e*s(t)*h*e*m*i*d(d(l))*e*c*o*e*ƒ*ƒ*i*c*i*e*n*t$.

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

Final Answer

x2−x−72=(x−9)*(x+8)

Want more problems? Check here!