Answer:
1. G IS A DEPENDENT VARIABLE
2.U IS THE INDEPENDENT VARIABLE
Step-by-step explanation:
G is a dependent variable because its values will rely on the values of U multiplied by 748. A dependent variable in most cases is isolated on one side of an equation ( mostly the left-hand side) and it value is affected by the values selected on the other side of the equation.
U is an independent variable because it stands on its own such that it does not rely on the behavior of another variable to determine its value/characteristic.Characteristic here i mean , U is freely selected without considering the behavior of other variable, thus it does not face any restrictions as compared to G.
You have to use the method of FOIL (first, outer, inner and Last)
9b*9b is first
9b*1 is outer
-1*9b is inner
-1*1 is last
Together, they form the expression 81b^2 + 9b - 9b - 1
Collect like terms and the answer is 81b^2 - 1