The answer is C. because 1.5 is the height while x is next to it to show the multiplication of years to height
The 2-point form of the equation of a line can be written as ...
... y = (y2-y1)/(x2-x1)·(x -x1) +y1
For your points, this is ...
... y = (1-5)/(3-6)·(x -6) +5
... y = (4/3)(x -6) +5
It can also be written as
... y -5 = (4/3)(x -6)
Volume of a cube is a side length cubed
So 7*7*7
Answer is 343 centimeters
By finding like denominators, you can add the fractions on each side. Then, compare by cross multiplying.