Question 036-x-

2.4 Equivalent Expressions - Simplifying polynomials
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0.36 x 2 + 0.63 x + 1.17

The given expression can be rewritten as a4x2+7x+13, where a is a constant. What is the value of a ?

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0.36 x 2 + 0.63 x + 1.17 The given expression can be rewritten as a

Hard-difficulty · SAT Math · Equivalent Expressions — Simplifying polynomials. Read the question above, select your answer, and check the full explanation below to understand exactly why the correct choice works.

Answer explanation

The correct answer is .09. It's given that the expression 0.36x2+0.63x+1.17 can be rewritten as a4x2+7x+13. Applying the distributive property to the expression a4x2+7x+13 yields 4ax2+7ax+13a. Therefore, 0.36x2+0.63x+1.17 can be rewritten as 4ax2+7ax+13a. It follows that in the expressions 0.36x2+0.63x+1.17 and 4ax2+7ax+13a, the coefficients of x2 are equivalent, the coefficients of x are equivalent, and the constant terms are equivalent. Therefore, 0.36 = 4 a , 0.63 = 7 a , and 1.17 = 13 a . Solving any of these equations for a yields the value of a . Dividing both sides of the equation 0.36 = 4 a by 4 yields 0.09 = a . Therefore, the value of a is 0.09 . Note that .09 and 9/100 are examples of ways to enter a correct answer.