Answer
a. 14
b. 14 is a solution to the equation.
Work Step by Step
$a.$
Replace x with 4 and y with 1:
$2(x+3y)=$
$=2(4+3\cdot 1)$
$=2(4+3)$
$=2(7)$
$=14$
b.
If the number 14 is the solution to the equation, then replacing z with 14 should result in a valid equation (the left side should be equal to the right side of the equality sign)
$5z-30=40\quad?$
$5(14)-30=40\quad?$
$70-30=40\quad?$
Yes, the equation is valid, 14 is a solution to the equation.
