# Algebra II

Use the equation of the exponential function whose graph passes through the points (0,-2) and (2,-50) to find the value of y when x = -2.

I know the formula is y=ab^x but I don't know what numbers to plug in.

Any help would be great.

Thanks.

1. 👍
2. 👎
3. 👁
1. first sub in (0,-2) to get
-2 = ab^0, but b^0 = 1
so a=-2
so far we have

y = -2b^x

now use the other point (2,-50)
-50 = -2(b^2)
b^2 = 25
b= ±5
however in exponentional equations the base is usually positve, so now you have

y = -2(5^x)

sub in x=-2 and you got it.

1. 👍
2. 👎

## Similar Questions

1. ### Exponential Growth and Decay

Can somebody please check my answers? 1. Identify the initial amount a and the growth factor b in the exponential function. g(x)=14*2^x a)a=14, b=x b)a=14, b=2

2. ### mathematics

The exponential decay graph shows the expected depreciation for a new boat, selling for \$3500, over 10 years. A coordinate graph is shown. The horizontal axis extends from 0 to 12 years. The vertical axis extends from 0 to 9500

3. ### college calc

Give a formula for the function illustrated using a vertical shift of an exponential function. The two points marked on the graph are A=(−1,17) and B=(1,2). The red horizontal line is given by y=1, and is a horizontal asymptote

4. ### math

i have more than one question so if u no any of the answers please tell me 1.) write the point-slope form of the equation of the line with slope -2 passing through the point ( -5, -9). 2.) write the point-slope form of an equation

1. ### math

Find the exponential function f(x)=Ca^x whose graph goes through the points (0,3) and (2,12).

2. ### Math(check)

1)Find the range of the relation [(-1,4)},(2,5),(3,5)}.Then determine whether the relation is a funtion. 4,5,5 is the range 4,5 is a function 2)Find f(-1),if f(x)= x^2-6x/x+2 (-1)^2-6(-1)/-1+2 1+6/-1+2 7/1 =7 3)Find f(a),if f(t)=

3. ### Alg 2 HELP!!

1.) Find an exponential function of the form y=ab^x whose graph passes through the points (2,48) and (5,3072) 2.) The variables x and y vary inversely. Use the given values to write an equation relating x and y. Then find y when

4. ### Math help and check

Which kind of function best models the set of data points (–1, 22), (0, 6), (1, –10), (2, –26), and (3, –42)? linear **** quadratic exponential none of the above 2. Which kind of function best models the set of data points

1. ### algebra

Write an equation of an exponential function that passes through the points (2, 18) and (5, 486)

2. ### WHOEVER HELPS ME WILL BE NAMED THE BOB

Question 10 of 19 Which graph represents the linear function y = 1/4x – 3? A. A line on a graph passes through the (-4, -4), (0, -3), and (4, -2). B. A line on a graph passes through the (-4, -2), (0, -3), (4, -4). C. A line on

3. ### Mathematics, Pre-Calculus

Help needed! Find the base of the exponential function whose graph contains the given points. 1. (2,16) 2. (1,10) 3. (3,64) 4. (3,1/343) 5. (4,1/625) 6. (3/2,27)