Which is a way to solve the equation 4^x=128 if you do not know a power of 4 that equals 128?

a) graph y=4^x and y=128, and look for points of intersection.

b) find what numbers multiplied by 4 equals 128

c) graph y=4x and y=128, and look for points of intersection

d) there is not way to solve this equation without already knowing a power of 4 that equals 128