Which expression is equivalent to (1 + 9x) 10 ? a) –10 – 90x. b) 11 + 9x. c) 10 + 90x. d) –11 – 9x

(1 + 9x)10 = (1 * 10) + (9x * 10) = 10 + 90x

It's  a simple multiplication form

(1 + 9x) 10

= (10. 1 ) + (10 . 9x)

= 10 + 90x

The correct answer is option C.

Hope this helps