The difference of two numbers is 20, and the difference of their squares is 800. What is the sum of the two numbers?

The sum of the 2 numbers is 40.

Step-by-step explanation:

x - y = 20

x^2 - y^2 = 800

x^2 - y^2 = (x - y)(x + y)  so:

800 = 20(x + y)

x + y = 800/20

so x + y = 40

rick has $1400 and sally has $1500

step-by-step explanation:

to find amount of money rick has after 10 years :

principal = $1000 , time = 10 years , rate = 4% annually

to find amount of money sally has after 10 years :

her friend gives to pay her $50 per year, therefore money she has after 10 years = 50 × 10 = $500

also, sally gets $1000 after 10 years,

therefore, total amount of money sally has after 10 years = 500 + 1000 = $1500

so, after 10 years : rick has $1400 and sally has $1500

to find the perimeter of the rectangle this is the expression:

x-9+x-9+3x-4+3x-4=138

if we simplify it:

8x-26=138

remember, 138 is what it all adds up to

the length is 11.5cm

the width is 57.5cm

the area is 661.25cm^2

the answers might not be correct use at own risk