Which system of equations has the same solution as the system below? 3x+3y=8 2x-y=5 a. 3x+3y=8 4x-2y=5 b. 3x+3y=8 4x-2y=10 c. x+y=8 2x-y=5 d. 9s+9y=22 18x+9y=45

Which of the angle pairs can be classified as vertical angles? ∠1 and ∠2 ∠2 and ∠4 ∠3 and ∠2 ∠4 and ∠1 ∠3 and ∠1

The equation x2 – 1x – 90 = 0 has solutions {a, b}. what is a + b?

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?