Y is partially constant and partially varies as x , when x is equal to 1 ,y equal to 7 when x equal to minus ,y is equal to 11 find the equation connecting xand y

Y equal to 3x+2
Y equal to 2x-3
Y equal to 4x+3
Y equal to 2x+4
Y equal to 3x+a

y = mx+b

to find m and b, solve
m+b=7
-?m+b = 11
when you decide what x is when y=11