Identify b and c: Identify b and c in the quadratic expression d2+10d+21. Compare d2+10d+21 with the standard quadratic form x2+bx+c. Here, b=10 and c=21.
Find two numbers: Find two numbers whose product is c(21) and whose sum is b(10). We need to find two numbers that multiply to 21 and add up to 10. The numbers 3 and 7 satisfy these conditions because: 3×7=21 (product is 21) (21)0 (sum is 10)
Write factored form: Write the factored form using the two numbers found in Step 2.The quadratic expression d2+10d+21 can be factored as (d+3)(d+7).
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