What is y intercept of equation represented:

Question

X Y
150 1047
125 872
100 697
75 522

a. -3
b. 0
c. 3
d. 172

I come up with totally different answers than these. Do you use the y2-y1/×2-×1 ?

Answer 1

Use the last two points to find the equation

slope = (697-522)/(100-75) = 175/25 = 7
so we have
y = 7x + b
sub in (75,522)
522 = 7(75) + b
b = -3

so we have y = 7x - 3
From your knowledge of y = mx + b, what do you think?

Answer 2

Thanks, could get 7 , but didn't know what to do after...