How to add and subtract rational numbers

Louise measured the perimeter of her rectangular scrapbook to be 154 cm. if the scrapbook is 45 cm wide, how long is the scrapbook?

To solve the system of equations below, pedro isolated the variable y in the first equation and then substituted it into the second equation. what was the resulting equation? { 5y=10x {x^2+y^2=36

Astore has apples on sale for three dollars or 2 pounds how many pounds of apples can you buy for nine dollars if an apple is approximately 5 ounces how many apples can you buy for nine dollars