If you plug in the respective numbers (x,y) you'll get the answer choice C. 19=4(4)+3 : 19=19
To find an average you add all numbers together then divide by the amount of numbers that you added. So if there are 4 numbers you would divide by 4. By going backwards you can find the answer. Multiply 5 by 4 and you get 20, which is the answer.
-10x + 1.5 because you get rid of the parenthesis so -2 times 5 is -10 ( -10x ) and then -2 times -0.75 equals positive 1.5 due to two negatives canceling out to positive hope this helped!