1. what is the value of the expression 2x-y=5 when x=2,y=1?
a. 8
b. a
c. a3
d.-7a

2. Add (7x-8=(8x10)
a. 15x2-18
b. 15x-18
c.15x2=18
d. 15x=18

3. Subtract (10x-9) from (5x-15)
a. 5x-6
b. 15x-24
c.5x-24
d.-5x4

4.What must be added to 3x2-2x=1 to get -x2=x-2?
a. -4x2=3x-3
b.2x2+x+1
c. x2-x-1
d. 2x2-x+1