Which of the following questions represents this equation? m + 13 = 21

What number when increased by 21 is equal to 13?

What number when subtracted from 13 is equal to 21?

The sum of what number and 13 is equal to 21?

What number when multiplied by 13 is equal to 21?

The sum of what number and 13 is equal to 21?

Step-by-step explanation:

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