Question

If 9(1-x) = 27Y and x-y=-11/2, find the value of x + y.​

Answer 1

Let 9(1-x) = 27y be equation one and let x-y = -11/2 be equation two

Simplify -11/2 into -5.5 and make x the subject in equation two by moving y to the other side as a positive value. So now you have x= -5.5+y (now let that be equation two)

Sub equation two into equation one so that you get 9(1-(-5.5+y)= 27y


Expand brackets 9(1+5.5-y)= 27y

Simplify brackets 9(6.5-y)= 27y

Expand brackets 58.5-9y= 27y

Take -9y to the other side as a positive number

58.5= -36y

Divide both sides by -36

y= 1.625

For x, substitute the value of y into equation two

x= -5.5+1.625

x= -3.875

To finally answer the question aadd the value of x and y together

-3.875+1.625= -2.25

Som the value of x + y is -2.25

Answer 2

-2.25

Explanation:

9(1-x) = 27Y

9-9x =27y

-9x -27y = -9 multiply all terms by -1

9x +27y =9 equation (1)

x-y= -11/2 equation (2)

by solving 2 equations

x= -3.875

y= 1.625

∴ x+ y = 1.625 +(-3.875) = -2.25