A: can't see the image.
8b: 9x + 7y = 10... equation 1
3x + y = 2...equation 2
make y the subject of the formula using equation 2
y=2 - 3x....equation 3
substitute for y using equation 3
9x + 7(2 - 3x) = 10
9x + 14 - 21x = 10
9x - 21x = 10 - 14
-12x = -4
divide both sides by -12
x = 1/3
substitute for x using equation 2
3(1/3) + y = 2
1 + y = 2
y = 2 - 1
y = 1
so x = 1/3 and y = 1
