Pls help! it’s a test. I’ll give 10 points.

72

Step-by-step explanation:

9*8 which is 72

Correct choice: 72

Step-by-step explanation:

Multiplication

In math, to multiply means to add equal groups. For example, 5 groups of 7 people add up to 5*7=35 people.

When multiplying variables (letters), it's common to omit the cross (x) or dot (.) signs to indicate multiplication.

The expression cd, when c and d are separate variables, should be interpreted as c by d.

We are given c=9 and d=8, thus

cd = 9*8 = 72

Correct choice: 72

x = -3

y = -18

step-by-step explanation:

to solve by substitution, substitute one variable and solve for the other. then substitute again to find the remaining variable.

x-1/3(3x-9) = -3 since y=3x-9 substittute y.

x-1/3(3x-9)=-3

x + x +3 = -3

2x+3=-3

2x+3-3= -3-3

2x=-6

x=-3

substitute again into y=3x-9

y=3(-3)-9

y=-9-9

y=-18