Writing equations in standard form: (1,-6) and (-7,2)

How would I write this in standard form? I already tried but I keep getting x+y=7 and it says it’s wrong so could someone help?

Add the two expressions 3.8b - 7 and 2.9b + 9 enter your answer in simplified form

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?

Question 13 (1 point) jerome is starting a new job. his contract states he will earn $42,000 the first year, and will get a 4% raise per year. which function s(x) represents jerome's salary after a certain number of years, x?