If the equation ax+by=-4 And bx+ay=1 Are satisfied by x=1 And y=2,find the value of a and b
let's see what happens when we sub in those given values ....
x=1 And y=2
ax + by = -4 ----> a + 2b = -4
bx + ay = 1 ---> b + 2a 1 OR b = 1 - 2a
now sub that 2nd into the first:
a + 2b = -4
a + 2(1 - 2a) = -4
a + 2 - 4a = -4
-3a = -6
a = 2
then in b = 1 - 2a
b = 1 - 2(2) = -3