Answer:
x = 5
Explanation:
3(x + 7) + 4 = 40 ( subtract 4 from both sides )
3(x + 7) = 36 ( divide both sides by 3 )
x + 7 = 12 ( subtract 7 from both sides )
x = 5
As a check
substitute x = 5 into the left side of the equation and if the value obtained is equal to the right side (40) then it is a solution
3(5 + 7) + 4
= 3(12) + 4
= 36 + 4
= 40
left side = right side
then x = 5 is the solution to the equation