Question

If 4x - 5y = 17 and x - 2y = 5 then find (x + y)​

Answer 1

4x-5y=17

4x=17+5y

x=(17+5y)/4 _____eqation 1

x-2y=5

x=5+2y ____equation 2 (put the value of equation 1)

(17+5y)/4=5+2y

17+5y=(5+2y)×4

17+5y=20+8y

-8y +5y=20-17

-3y=3

y=-1

(put value of y in equation 2)

x=5+2y

x=5+2×(-1)

x=5-2

x=3

so, x+y=3+(-1)

=2