12a+7c=315
how to solve for/what is a?

Ineed with number 17 i don’t get it at alll

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

Johnny rode his bike to a friends house 4 blocks down the street in his neighborhood. he immediately rode back home once he realized his friend was unable to play. what was his displacement for the total bike ride trip? what could you use as a reference point ? show the steps to solve this problem.