Exponential Functions: Find the equation through the points A and B in the form y = a b x

Question 1:

A is (0,4) and
B is (1,8)
y = 4 × 2 x

Question 2:

A is (0,-4) and
B is (2,-100)
y = -4 × 5 x

Question 3:

A is (0,2) and
B is (2,18)
y = 2 × 3 x

Question 4:

A is (1,8) and
B is (5,128)
y = 4 × 2 x

Question 5:

A is (3,-135) and
B is (5,-1215)
y = -5 × 3 x

Question 6:

A is (3,32) and
B is (4,64)
y = 4 × 2 x