Ineed to find y=mx+b. i found m but i forgot how to find b.

Y = mx + b. This linear graph passes through A(0,50) and B(10,51)

m = (y₂-y₁)/(x₂-x₁)
m= (51-50)/10-0)
m=(1)(10)

y = (1/x) + b. To find b, you plugin the coordinates of either A or B,
say A(0,50):

50 = (1/10).(0) + b
50 = 0+b  and b= 51

Hence the equation is y =0.1x + 50

8-2x+3x2=6 and six is your answer