1. Which of the following expressions is 5 times as much as the sum of r and s? *
A. 5 × r + s
B. 5 + r + s
C. r + s × 5
D. (r + s) × 5

Answer is D

Step-by-step explanation:

you want to multiply 5 to r and s so then r and s. so the forth one would be distributed into both r and s.

a4 - 3a2 - 1

step-by-step explanation:

step   1   :

equation at the end of step   1   :

  ((a4) -   3a2) -   1

step   2   :

trying to factor by splitting the middle term

2.1     factoring   a4-3a2-1  

the first term is,   a4   its coefficient is   1 .

the middle term is,   -3a2   its coefficient is   -3 .

the last term, "the constant", is   -1  

fist on the left goes with the third on the right. second on the left goes with the fourth on the right. third on the left goes with the second on the right. the fourth on the left goes with first on the right