Ayearbook printer charges based on the number of pages printed. here is a table that shows the cost of some recent yearbooks.
number of pages 50 100 150 200
cost 1.55 2.25 2.95 3.65
which equation gives the cost, y, in terms of the number of pages, x?
a.
y = 0.014x + 49.15
b.
y = 0.014x + 1.55
c.
y = 0.014x + 0.85
d.
y = 58.8x + 0.85

So y=mx+b

cost=m(number of pages)+b

cost=y
# of pages=x

so points are
(x,y)
(50,1.55)
(100,2.25)
(150,2.95)
(20,3.65)

so solve for slope/m you do  (y₁-y₂)/(x₁-x₂) so
just use any for example
(1.55-2.25)/(50-100)=-0.70/-50=1 times 0.7/50=7/500= (to convet to decimal form) 14/1000=1.4/100=0.14/10=0.014/1=0.014

slpoe is 0.014

y=0.014x+b

input one of the points exg 50 for x and 1.55 for y and solve for b
1.55=0.014(50)+b
1.55=.7+b
subtract .7 from both sides
0.85=b

so the equation is
y=0.014x+0.85

which is C