Question

find the value of x + Y for 15 X + 17 Y =21; 17x+15y=11.​

Answer 1

Answer:

x + y = 1

Step-by-step explanation:

15 x + 17 y = 21---------1

17x + 15 y = 11 --------2

Subtract 2 from 1.

15x + 17y - 17x - 15y = 21 -11

-2x + 2y = 10

2(y - x) = 10

y - x = 5

y = 5 + x

substitute the value of y into the 1st equation.

15x + 17(5+x) = 21

15x + 85 + 17x = 21

32x = -64

x =  - 2

Substitute the value of x

15(-2) + 17 y = 21

-30 + 17 y = 21

17y = 51

y = 3

x + y = -2 + 3

x + y = 1