Question

A student bought a calculator and a textbook for a course in algebra

Answer 1

To solve the system by substitution, first, we substitute the second equation in the first one and get:

`4y+20+y=145.`

Adding like terms we get:

`5y+20=145.`

Subtracting 20 from the above equation, we get:

`5y=145-20=125.`

Dividing by 5, we get:

`y=25.`

Substituting y=25 in the second equation of the system, we get:

`x=4(25)+20.`

Simplifying the above result, we get:

`x=100+20=120.`

Answer:

`(120,25)\text{.}`