20 POINTS! PLEASE HELP! WILL GIVE BRAINLIEST! Which expression should you simplify to find the 90% confidence interval, given a sample of 90 people with a sample proportion of 0.25? O A. 0.25 +90 0.25(1-0.25) 1.645 OB. 0.25 + 1.645-0.25 90 0.25(1-0.25 90 O C. 0.25 +1.645. . D. 0.25 +1.645. 0.25(1-0.25) 90 SUBMIT​

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