first of all, notice that each equation is divisible by 4
new equations:
8x + 9y = -4
9x + 8y = -4
multiply 1st by 8 ---> 64x + 72y = -32
multiply 2nd by 9 --> 81x + 72y = -36
subtract them
17x= -4
x = -4/17
into the 1st:8(-17/4) + 9y = -4
times 4
-136 + 36y = -16
36y = 120
y = 10/3
32x+36y+16=0
36x+32y+16=0
Find x and y
1 answer