Someone : (
at time x=0, water begins to drip steadily out of a water tank. after 1 hour, there are 7.8 gallons of water in the tank. after 9 hours, 6.2 gallons remain. write a linear function rule that models the number of gallons of water y left in the tank for any number of hours x.

y = -0.2x + 8

Step-by-step explanation:

To write a linear function, calculate the rate of change of the gallon of water leaving the tank and the starting level.

The function will describe the number of gallons over time or (time, gallons).

This means the function has data points (1, 7.8) and (9, 6.2).

Use the rate of change or slope formula to calculate it.

This means that for the formula y = mx+b then m = -0.2.

This also means that after losing 0.2 gallons the first hour it was at 7.8. So the starting value is 8 gallons.

The equation is y = -0.2 x + 8.

answer

the correct answer is

explanation

the given function is

the excluded values are obtained by solving:

we factor to obtain:

the excluded values are

-3

step-by-step explanation:

a drawing really does here:

so i draw the horizontal line y=2 and the vertical line x=-2 at this intersection i put b (this is where my right angle is going to be).   so point b is at (-2,2).   point a is 5 units long and is also on y=2 so this point has to be (3,2) or (-7,2) -doesn't matter i will go with (3,2).

now we know c is at (-2,y) we don't know the y yet bet we know that c is on x=-2.

we have the area of the triangle is .5bh=12.5

we know the base length is 5 (ab)

we have the height is (2-y) if you look at your

plug in

.5(5)(2-y)=12.5

solve for y to get the y-coordinate for c

2.5(2-y)=12.5

divide both sides by 2.5 giving:

2-y=5

now subtract 2 on both sides

-y=3

y=-3