Q. 25x2−40x+16Which of the following is equivalent to the given expression?Choose 1 answer:(A) (5x−4)2(B) (5x−2)(5x−8)(C) (5x+4)2(D) (5x−4)(5x+4)
Finding the Product: The product of the coefficient of x2 and the constant term is 25×16=400. We need two numbers that multiply to 400 and add up to −40. The numbers −20 and −20 fit this requirement because (−20)×(−20)=400 and (−20)+(−20)=−40.
Identifying the Numbers: Now we can write the quadratic expression as a perfect square because it follows the pattern of a2−2ab+b2, which is equivalent to (a−b)2. Here, a is 5x and b is 4, so the expression 25x2−40x+16 can be written as (5x−4)2.
Writing as a Perfect Square: We can check our factoring by expanding (5x−4)2 to verify that it gives us the original expression. Expanding (5x−4)2 gives us (5x−4)(5x−4)=25x2−20x−20x+16=25x2−40x+16, which matches the original expression.