Question

michael was driving at a constant speed of 60 mph when he crossed the sandy river .after 1 hour he passed a highway marker for mile 84 . write an equation in point slop form and find which highway marker he will pass 90 minutes after crossing the sandy river

Answer 1

speed of Michael = 60 mph

distance traveled in 1 hour = speed* time= 60 *1 = 60 miles

marker crossed after 1 hour = 84

so start point of Michael had marker = 84-60 =24

to write linear equation, lets consider a general linear equation y = mx + c

where m is slope and c is constant, y is marker and x is actual distance traveled from starting point

putting y = 84 x = 60 and y =24 and x = 0 in the equation we get

84 = m*60 + c

24 = m*0 + c

on  solving,

m = 1  c = 24

so the equation is y = x + 24

distance traveled in 90 minutes after crossing sandy river = 60*90/60 = 90 miles

total distance traveled from starting point = 90+60 = 150

putting  x = 150 in y =x+24

y = 174

highway marker he will pass 90 minutes after crossing the sandy river = 174

Answer 2

Slope intercept form is y=mx+b so use your numbers  to fill in the blanks 

heres an example: