If 3a+5=12, what is the value of 6a+14?

For example, choice A is incorrect because if the value of 10x + 3 were 4, then it would follow that x = 0.1, and the value of 5x + 6 would be 6.5, not 10.

Step-by-step explanation:

The answer is

3a + 5 = 12

subtract 5 from both sides

3a = 7

divide by 3 on both sides to isolate "a"

a = 7/3

Substitute 7/3 for "a" in the second equation

6(7/3) + 14

6 multiplied by 7/3 = 42/3 = 14

14 + 14 = 28

in simplified version   it would be x ≤-4

step-by-step explanation:

multiply each term in x ≤-4 by -1

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!