Answer:
D.
Step-by-step explanation:
In this case the temperature depends on the hour. So temperature is your X and hour is your Y variable. When h=0, x=0. So the 21*C is you x=0 or y-int point.
If we are trying to match the equation for a line of y=mx+b, 21*C=b.
Our rate of change is -4*C/h, which is our m variable.
So y=(-4)x+(21)
OR in this case, t=-4h+21.
Answer D.
<span> x − 2y = −1 => x = 2y -1
2x + y = −12
2(2y - 1) + y = -12
4y - 2 + y = -12
5y = -10
y = -2
x = 2</span>·(-2) - 1
x = -4 - 1
x = -5
Answer <span>D (-5,-2)</span>
Answer:
Step-by-step explanation:
Perimeter is simply length + width. They gave us that the length is 2 feet plus 2 times the width:
Subtract 2 from both sides to get 23 = 2w + w
Combine like terms to get 23 = 3w
Divide by 3 to get 
feet
The problem gives you X, so replace X witht he given vaule and solve for y:
y = -0.1x^2 + 4X
X = 40
y = -0.1(40)^2 +4(40)
y = -0.1(1600) + 160
y = -160 + 160
y = 0
