Should be four times to get in between 9 and 10
X = 15
X + 90 = 7x
X = 7x - 90
X - 7x = -90
-6x = 90
Divide both sides by -6
X = 15
Answer:
First one is c because 3 1/2 - 1/2=3
Second one is also c because 0.9x2=1.8
And third one c is because 2 2/3:3/1=1 1/8
Y = mx + b, m = slope and b = y-intercept
Because you don't have the y-intercept, you take the equation and replace x and y with the values given, then solve for b and replace b in the original equation with the value found.
y = 2/3x + b
0 = (2/3)(-3) + b
0 = -2 + b
2 = b
y = 2/3x + 2 is the answer