Question

Margot spent $400 this month on propane to heat her home. Her propane company charges $3 per gallon, and she received a $20 discount for paying in cash. To determine how many gallons of propane she bought, solve for x in the following equation: 400 = 3x - 20.

a) x = 140
b) x = 140 + 20
c) x = 120
d) x = 120 + 20

Answer 1

To solve the equation 400 = 3x - 20, isolate x by adding 20 to both sides and then dividing both sides by 3. The value of x is 140.

Step-by-step explanation:

To solve for x in the equation 400 = 3x - 20, we need to isolate x. To do this, we can start by adding 20 to both sides of the equation. This gives us 400 + 20 = 3x - 20 + 20, which simplifies to 420 = 3x. Next, we divide both sides of the equation by 3. This gives us 420/3 = 3x/3, which simplifies to 140 = x. Therefore, the value of x is 140.