Identify a, b, c: Identify a, b, and c in the quadratic expression 2x2+9x+7. Compare 2x2+9x+7 with ax2+bx+c. a=2b0b1
Find numbers multiply add: Find two numbers that multiply to a∗c (which is 2∗7=14) and add up to b (which is 9).We need to find two numbers that satisfy these conditions.After checking possible pairs that multiply to 14 (1 and 14, 2 and 7), we see that 2 and 7 add up to 9.So the two numbers are 2 and 7.
Rewrite middle term: Rewrite the middle term 9x using the two numbers found in Step 2.2x2+9x+7 can be written as 2x2+2x+7x+7.
Factor by grouping: Factor by grouping.Group the terms into two pairs: 2x2+2x and 7x+7.Factor out the common factor from each pair.From the first pair, factor out 2x: 2x(x+1).From the second pair, factor out 7: 7(x+1).
Write factored form: Write the factored form of the expression.Since both groups contain the factor (x+1), factor this out.The factored form is (2x+7)(x+1).
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