The population of algae in an experiment has been increasing by 40% each day. If there were 20 algae at the beginning of the experiment, predict the number of algae in 7 days.
First, complete the equation:
Future Amount = [?](1+[]0

The equation is y = 20(1.40)^x

where x is the number of days and y is the future amount after x days go by

The 1.40 is from the fact that 1+r = 1+0.40 = 1.40, where r is the decimal form of 40%, so r = 0.40

Plug in x = 7 to get

y = 20(1.40)^x

y = 20(1.40)^7

y = 210.827008

y = 211

We round to the nearest whole number since it doesn't make much sense to have a fractional portion of an algae. After 7 days, there are about 211 algae.

c. y = 1/4 x + 5

step-by-step explanation:

first, put the equation of the line on the graph into slope-intercept form

(y = mx + b):   y = -4x + 8

second, a perpendicular line has to have "an opposite/reciprocal slope" to the original slope. so, find the "m" value in your original equation (it's -4, right? )

original slope: m = -4   perpendicular slope: change the sign to its opposite and find the reciprocal ("flip" the number)

new slope is now positive (b/c the original slope was negative 4), and it's 1/4 (not the original slope of 4 or 4/1)