Your base is the length on the bottom your height is that line in the middle of the triangle. Multiply those then divide by two to get the area always. But since its long and its a prism you have to multiply by 12.
Volume will always have the unit 3 in it and the measuring unit will depend on what is says for example in this problem its inches so its inches cubed (3).
For a y-intercept, set in your equation. Remember that a y-intercept intercepts the y-axis, which is found at . Thus, setting will give you the place where your equation intercepts the y-axis.
For an x-intercept, do the opposite, set . This is because the x-axis is found at . Similar to the y-intercept, this will find you the point where your equation intercepts the x-axis.