Your quiz grades are 98, 82, 89, and 94. What score on the fifth quiz will make your average quiz grade at least 90? Write an inequality to support your answer.

87

Step-by-step explanation:

98+82+89+94+X / 5 = 90

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