Question

The graph of y = -3x + 2 intersects the graph of an exponential function at (-1, 5). Which of the following could be the exponential function?

a) y = 10(2)
`image`
b) y = 10(0.5)
`^(x)`
c) y = 5
`^(x)`
d) y = 5(2)
`^(x)`

Answer 1

`a) y = 10(2)^x`

Explanation:

In order to solve this you just need to evaluate the options given with the values of the point that is given in order to see if that point is a possibility in that function, remember to use the value of x to avaluate and if the result is the same as the points value for y then that poin is part of the graph.

`a) y = 10(2)^x`

`y=10(2)^x\\y=10(2)^-1\\y=10*(1)/(2) \\y=5`

Remember that when elevating to negative numbers the ecponent becomes a numerator, so the only option that is correct would be the first one
`a) y = 10(2)^x`

Answer 2

Of the function choices offered, only the first includes (-1, 5) in its graph.
a) y = 10(2)^x