Question

$8x + 5y = 420 \\5x + 8y = 321$

Answer 1

8x+5y=420×5
5x+8y=321×8

40x+25y=2100--1
40x+64y=2568---2

Now subtracting above equation
We get,

-39y=-468
y=12


putting y in equation 1

40x+300=2100
40x=1800
x=45