For what value of x is the figure a rectangle?

Step-by-step explanation:

step 1. 4x + 27 + 3x = 90 (definition of a rectangle)

step 2. 7x = 63 (collect like terms. subtract 27 from both sides)

step 3. x = 9 (divide both sides by 7)

step-by-step explanation:

you can add the two numbers and divide the result by 2. or you can find the gap between the two numbers and add half of this to the smaller number.

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!