Please help and explain if so thank you!

Answer:
y = 7x + 1
Step-by-step explanation:
Slope m = 7 and pass-thru point (1,8)
Start with y = mx + b. Subst. 9 for y, 7 for m and 3 for x, obtaining:
8 = 7(1) + b. Then b = 1.
The desired equation is y = 7x + 1.