If you wanted to make the graph of y = 3x + 1 steeper, which equation could you use?

Y = 3x + 1 

y = mx + b 

Where,
m = Rise/Run (Slope)
b = y-intercept

Changing the y intercept wouldn't change the steepness, but instead it would change where the graph would cross the y-axis (vertical axis). 

The slope is the rise over run. So for the current graph you would go up 3 and then over 1. If you increased the number by any amount you would be going higher while going the same distance to the right. As a result the line would be getting steeper and steeper. 

In other words the answer will be the one with a higher slope. If the slope is a fraction take our original slope and find a common denominator. Then compare. 

I hope that this helps!

The answer is $9.90 with rounding to the nearest tenth