Factor 4x^2-8x-5

Problem

4*x2−8*x−5

Solution

1. Identify the coefficients of the quadratic expression in the form a*x2+b*x+c Here, a=4 b=−8 and c=−5

2. Calculate the product of a and c which is 4⋅(−5)=−20

3. Find two numbers that multiply to −20 and add to the middle coefficient b=−8 These numbers are −10 and 2

4. Rewrite the middle term −8*x using the two numbers found: 4*x2−10*x+2*x−5

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

2*x*(2*x−5)+1*(2*x−5)

6. Factor out the common binomial (2*x−5)

(2*x−5)*(2*x+1)

Final Answer

4*x2−8*x−5=(2*x−5)*(2*x+1)

Want more problems? Check here!