A system of equations is given below: y = 3x + 4
2x + 3y = 10
Which of the following steps could be used to solve by substitution? (4 points)

A: 3x + 4 = 2x + 3y

B: 2x + 3(3x + 4) = 10

C: 2(3x + 4) + 3y = 10

D: 3(y = 3x + 4)

Match each expression with its simplified form.

Afruit stand has to decide what to charge for their produce. they need $10 for 4 apples and 4 oranges. they also need $15 for 6 apples and 6 oranges. we put this information into a system of linear equations. can we find a unique price for an apple and an orange?

International calls require the use of a country code. many country codes a 3-digit numbers. country codes do not begin with a 0 or 1. there are no restrictions on the second and third digits. how many different 3-digit country codes are possible?