Y = mx + b....m is the slope and b is the y intercept
slope(m) = 5...(4,0)...x = 4 and y = 0
now we sub our info into y = mx + b...we r looking for b, the y intercept
0 = 5(4) + b
0 = 20 + b
-20 = b
so ur equation is y = 20x - 20...but we need it in standard form
Ax + By = C
y = 20x - 20....subtract 20x from both sides
-20x + y = -20...multiply by -1 to make x positive
20x - y = 20 <== standard form
Answer:
Growth when: b>1.
Decay when: 0<b<1.
Step-by-step explanation:
Any function in the form 
, where a > 0, b > 0 and b not equal to 
is called an exponential function with base b.
If 0 < b < 1 this is an example of an exponential decay.
The general shape of an exponential with b > 1 is an example of exponential growth.
Hence,
An exponential function is expressed in the form , The relation represents a growth when b >1 and a decay when 0<b<1.
The first term, a, is 2. The common ratio, r, is 4. Thus,
a_(n+1) = 2(4)^(n).
Check: What's the first term? Let n=1. Then we get 2(4)^1, or 8. Is that correct? No.
Try this instead:
a_(n) = a_0*4^(n-1). Is this correct? Seeking the first term (n=1), does this formula produce 2? 2*4^0 = 2*1 = 2. YES.
The desired explicit formula is a_(n) = a_0*4^(n-1), where n begins at 1.
