Question

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

Answer 1

x=-3.875

y=1.625

x+y=5.5

Explanation:

Given:

9(1-x)=27y

x-y=-11/2

then:

x=y-11/2 OR 5.5

substitute:

9(1-[y-5.5])=27y

9-9[y-5.5]=27y

9-9y+49.5=27y

simplifying:

36y=58.5

y=1.625

x=1.625-5.5=-3.875

Proof:

x-y=5.5 then -3.875-1.625=-5.5 =-11/2

9(1-x)=27y then 9(1-(-3.875))=27(1.625) then simplified

9(4.875)=43.875 or 43.875=43.875