book Maths Puzzle Numerical Ability

How do I first simplify then solve:
-1/9u^-5*(45u^-4)

Read Solution (Total 0)

book Other Question

The worksheet says:
Use substitution to solve each system of equations. If the system does not have exactly one solution, state whether it has no solution or infinitely many solutions.

The problem:
3x-y=4
2x-3y=-9
explain how you would decide whether the product of three numbers is positive or negative