Check whether the solution exists or not, if it exists give the reason of existence and solve the system of equations. x + y + z = d
x + (1 + d)y + z = 2d
x + y + (1 + d)z = 0

Iam not sure , but probably 750 or 7.5

If gravity is one third on mars then weight also one third on mars

Look, when you want to do something like put it like x^2. x2 could mean x² or x₂. so to clear confusion, know the notation. to find the product multiply the x's and you get -8x and the y's and you get 6y. since it's all being multiplied it is just -8x6y, or answer a. although the better answer is -48xy(combining -8 and 6) because you should multiply constants whenever you can.