Answer to a) Lin can use 6 and 4 because (6x8=48) and (4x12=48) making both x values the same 48x
Answer to b) the smallest numbers would be 3 and 2 because (3x8=24) and (2x12=24) making both x values the same 24x
Step by step for elimination method
So this is what you do, multiply the 1st equation by 3 and the 2nd equation by 2 so your x values are the same
3(8x + 15y = 58) = 24x + 45y = 174
2(12x - 9y = 150) = 24x - 18y = 300
Subtract your new equations
63y = -126
Divide by 63 to solve for y
y = -2