Answer:
(-5, 3)
Step-by-step explanation:
Elimination seems like the best method to use here.
x+y=-2
x-y=-8
---------
2x=-10
Divide everything by two
x=-5
Now plug it back into one of the original equations,
-5+y=-2
Add 5 to everything
y=3
Answer:
a*sqrt(x+b) + c = d
or
a*√(x+b) + c = d
Step-by-step explanation:
The Newton`s law of cooling:
T = R + ( To - R ) * e ^(-kt )
We know that: T = 32° F ( the water freezes at 32° F ), To = 55° F, R = 5° F
and the cooling rate is: k = 0.012.
33° F = 5° F + ( 55° F - 5° F ) · 2.72^(-0.012 t )
33 - 5 = 50 · 2.72^(-0.012 t)
27 = 50 · 2.72^(-0.012 t)
2.72^(-0.012 t) = 27/50
1 / 2.72^(0.012 t) = 0.54
2.72^( 0.012 t ) = 1 : 0.54 = 1.85
0.012 t = log(base e) 1.85 = ln 1.85 = 0.6
t = 0.6 : 0.012 = 50
Answer: It would take 50 minutes.
So there are two ways.
First you could solve for y and plug it into the calculator. one equation for y1 and another for y2. Then go 2nd trace and press 5 and then press enter 3 times to find the intersection.
the second way is to solve by hand. I would suggest solve the first equation for y and plug the equation solved for y into the other equation. so y = -3x + 9 and 3x-5y=15. Then you could do 3x - 5(-3x+9) = 15. Finally solve for x and plug in x into both equations to see if you get the same y value.
The answer should be (10/3, -1)
Answer:
1 Pen cost $2.25
Step-by-step explanation:
Assume:
Cost of Pen = a
Cost of pencil = b
Cost of notebook = c
a = 3b -------------------(1)
c = 4a -------------------(2)
2a + 6b + c = $18 -----(3)
From equation (1), b = a ÷ 3 ---------(4)
Substitute equations (2) and (4) in equation (3)
2a + 6 * (a ÷ 3) + 4a = $18
2a + 2a + 4a = $18
8a = $18
a = $2.25
Therefore, 1 Pen cost $2.25
