The equation y = 0.75x + 1.5 models the data on a scientist’s scatter plot, where x is the amount of water a plant receives in milliliters, and y is the height in centimeters. if the height of the plant is 16.5 centimeters, how much water did it receive?

First plug in 16.5 cm for y that is given to you. Your equation should look like this 16.5=0.75x+1.5. Then subtract 16.5-1.5 you should get 15. Your equation should now look like this 15=0.75x. Now to get x alone divide 15/0.75. You should get x=20. You can check by plugging in x to the original equation to see if each sides are equal.

You for posting your question here. 

the major axis is 18. the major axis is 2a.
the minor axis is 10. the minor axis is 2b.

x^2/ 25 + y^2/ 81 = 1