Factor 3x^2-11x-20

Problem

3*x2−11*x−20

Solution

1. Identify the coefficients of the quadratic expression a*x2+b*x+c where a=3 b=−11 and c=−20

2. Calculate the product of a and c which is 3×−20=−60

3. Find two numbers that multiply to −60 and add to the middle coefficient b=−11 These numbers are −15 and 4

4. Rewrite the middle term −11*x using the two numbers found: −15*x+4*x

3*x2−15*x+4*x−20

5. Factor by grouping by taking the greatest common factor out of the first two terms and the last two terms.

3*x*(x−5)+4*(x−5)

6. Factor out the common binomial (x−5)

(3*x+4)*(x−5)

Final Answer

3*x2−11*x−20=(3*x+4)*(x−5)

Want more problems? Check here!