Question

a) X + y =5
2x - y =9

b) 3x - y =10
X + y =18

Answer 1

A) x = 5 - y ==> 2(5-y) - y = 9 ==> 10 - 2y - y = 9 ==> 3y = 1 ==> y = 1/3
x = 5 - 1/3 ==> x = 15/3 - 1/3 ==> x = 14/3

B) x = 18 - y ==> 3(18 - y) - y = 10 ==> 54 - 3y - y = 10 ==> 4y = 44 ==> y = 11
x = 18 - 11 ==> x = 7