Which function is graphed below?

Two cyclists 84 miles apart start riding toward each other at the same. one cycles 2 times as fast as the other. if they meet 4 hours later, what is the speed (in mi/h) of the faster cyclist?

Why is it so easy to buy on impulse and overspend with a credit card? what could you do to counteract this tendency?

Write the slope intercept equation for line ab.