Can someone me. the question says work out the equation for each graph will give 25 points

In exponential growth functions, the base of the exponent must be greater than 1,how would the function change if the base of the exponent were 1? how would the fiction change if the base of the exponent were between 0and 1

What is the y-intercept of the line given by the equation

Find the solution of this system of equation -7x+y=-20 9x-3y=36