How do you solve this math question?

The perimeter of a triangle is 69 cm. the first is 5 cm shorter than the second side. the third side is twice as long the first side. find the length of each side

Which steps could be part of the process in algebraically solving the system of equations, y+5x=x^2+10 and y=4x-10

If f(x) and g(x) are inverse functions of each other, which of the following shows the graph of f(g(x)