SAT官方每日一题附答案和解析[数学](2020年7月1日)
日期:2020-07-01 07:12
(单词翻译:单击)
每日一题
Mathematics>Standard Multiple Choice
Read the following SAT test question and then click on a button to select your answer.
(a+3)(2a^2-5a+7)
Which of the following is equivalent to the expression above?
A.2a^3-5a+21
B.2a^3+a^2-8a+21
C.2a^3+6a^2-5a+7
D.2a^3+11a^2+22a+21
答案和解析
答案:B
解析:
Choice B is correct. When multiplying polynomials, be sure to multiply each term in the first polynomial by each term in the second polynomial.
This can be done as follows: (a+3)(2a^2-5a+7)=2a^3-5a^2+7a+6a^2-15a+21
Combine like terms to get:
2a^3+a^2-8a+21
The equivalent expression is 2a^3+a^2-8a+21.