Identify a, b, c: Identify a, b, and c in the quadratic expression 3k2−8k+5. Compare 3k2−8k+5 with ax2+bx+c. a=3b0b1
Find two numbers: Find two numbers whose product is a∗c (3∗5=15) and whose sum is b (−8).We need to find two numbers that multiply to 15 and add up to −8.The numbers −3 and −5 work because:−3∗−5=15−3+−5=−8
Rewrite middle term: Rewrite the middle term −8k using the two numbers found in Step 2.3k2−8k+5 can be rewritten as 3k2−3k−5k+5.
Factor by grouping: Factor by grouping.Group the terms: (3k2−3k)+(−5k+5).Factor out the common factors from each group.3k(k−1)−5(k−1).
Factor out common binomial: Factor out the common binomial factor (k−1).(3k−5)(k−1) is the factored form of 3k2−8k+5.