Identify a, b, c: Identify a, b, and c in the quadratic expression 3x2+20x+25. Compare 3x2+20x+25 with ax2+bx+c. a=3b0b1
Find two numbers: Find two numbers whose product is a∗c (3∗25=75) and whose sum is b (20).We need to find two numbers that multiply to 75 and add up to 20.15∗5=7515+5=20Two numbers: 15,5
Rewrite middle term: Rewrite the middle term 20x using the two numbers found in Step 2.3x2+15x+5x+25
Factor by grouping: Factor by grouping.Group the terms: (3x2+15x)+(5x+25)Factor out the common factors from each group.3x(x+5)+5(x+5)
Factor out common binomial: Factor out the common binomial factor (x+5).(3x+5)(x+5)