4x + y = 24
y=-4x+24
Substitution

Step-by-step explanation:

4x -24=-y

-24-4x=y

then do calculation

infinite solutions

Step-by-step explanation:

substitute y in the first equation

4x+(-4x+24)=24

4x and -4x cancel out

24/24=1

or solve for x, you should also get 1

therefore, infinite solutions. you can also try using a graphing calculator

b. 1.25 hr

step-by-step explanation:

if you have a constant speed of 60 mph, then you have a ratio between 60 mi. to 1 hr. dividing both sides by 60 we get the ratio

1 mi. to

then mult. both sides by 75 we get the ratio

75 mi. to

simplifying we get

75 mi. to

or 1.25 hr.