Cory earns $20 for every lawn he mows and $9 for every hedge he trims. he uses the expression 20x + 9y to keep track of his earnings. part a: identify the coefficients and variables in the expression. part b: how many terms are in the expression, what are they, and how do you know? part c: which term in the expression shows the total earned from trimming hedges? .

Ascientist has 50 grams of a radioactive element. the amount of radioactive element remaining after t days can be determined using the equation (1) after two days the scientist receives a second shipment of 50 grams of the same element. the equation used to represent the amount of shipment 2 remaining after t days is 10) - 50 which of the following is an equivalent form of the expression for the amount remaining in shipment 2? what’s the answer?