Hi,
we need to substitute 4 and 1 in the equation, so for every y, we replace it with a 1 and every X with 4 as X= 4, Y = 1
equation: X + X (X + Y) + Y
equation after substituting the numbers: 1 + 1 (1 + 4) + 1
Bidmas rules apply.
expand the bracket first. 1 (1 + 4)=
1 X 1= 1
1 X 4= 4
1 + 4 = 5
then the equation becomes: 1 + 5 + 1= 7
your answer is 7 if you want to evaluate it.
your answer is 1 + 1 (1 + 4) + 1 if you need the equation.
, hope that helps :)