Atextbook store sold a combined total of 266 math and biology textbooks in a week. the number of math textbooks sold was 54 more than the number of biology textbooks sold. how many textbooks of each type were sold?

Let m and b represent the numbers of math and biology books sold, respectively. The problem statement tells you ...

... m + b = 266

... m - b = 54 . . . . . . . 54 more math books were sold

Adding these two equations gives you ...

... 2m = 320

... m = 160 . . . . . divide by 2

... b = 160 -54 = 106 . . . . 54 fewer biology books were sold.

160 math textbooks and 106 biology textbooks were sold in a week.

hello from mrbilldoesmath!

answer:

25x^2 + 90x + 84

discussion:

mn(x) = m(n(x)) = m( 5x + 9) =

(5x + 9)^2 + 3 =>

25x^2 + 90x + 9^2 + 3 =

25x^2 + 90x + 84                 (as 9^2 = 9*9 = 81)

which is the second choice

regards,  

mrb

p.s.   i'll be on vacation from friday, dec 22 to jan 2, 2019. have a great new year!