Bianca wrote the steps for her solution to the equation 2.3 + 8(1.3x – 4.75) = 629.9. she left out the description for the last step.

what is the missing step of her solution?

a: add 10.4 to both sides.
b: add negative 10.4 to both sides.
c: multiply both sides of the equation by 10.4.
d: divide both sides of the equation by 10.4.

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!

if i put something wrong your not gonna like it so rather not say nothing.