Question

what are the points where 4x-y=9 and x-3y=16 intersect thanks

Answer 1

y=4x-9
x=16+3y --- this push in the first equation and will get
y=4(16+3y)-9
y=64+12y-9
-11y=55
y=55/(-11) =-5
y=-5

x=16+3y
x=16+3(-5)
x=16-15
x=1

x=1
y=-5