9514 1404 393
Answer:
$2.50
Step-by-step explanation:
The question asks for the total cost of a notebook and pen together. We don't need to find their individual costs in order to answer the question.
Sometimes we get bored solving systems of equations in the usual ways. For this question, let's try this.
The first equation has one more notebook than pens. The second equation has 4 more notebooks than pens. If we subtract 4 times the first equation from the second, we should have equal numbers of notebooks and pens.
(8n +4p) -4(3n +2p) = (16.00) -4(6.50)
-4n -4p = -10.00 . . . . . . . . . . . simplify
n + p = -10.00/-4 = 2.50 . . . . divide by the coefficient of (n+p)
The total cost for one notebook and one pen is $2.50.
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<em>Additional comment</em>
The first equation has 1 more notebook than 2 (n+p) combinations, telling us that a notebook costs $6.50 -2(2.50) = $1.50. Then the pen is $2.50 -1.50 = $1.00.
One could solve for the costs of a notebook (n) and a pen (p) individually, then add them together to answer the question. We judge that to be more work.
Answer:
<em>x = 2</em>
Step-by-step explanation:
<u>Exponential Equations</u>
Solve:
![5^{2x-1}+5^{x+1}=250](https://tex.z-dn.net/?f=5%5E%7B2x-1%7D%2B5%5E%7Bx%2B1%7D%3D250)
Separate each exponential:
![5^{2x}5^{-1}+5^{x}5^{1}=250](https://tex.z-dn.net/?f=5%5E%7B2x%7D5%5E%7B-1%7D%2B5%5E%7Bx%7D5%5E%7B1%7D%3D250)
Operating:
![\displaystyle \frac{5^{2x}}{5}+5^{x}5=250](https://tex.z-dn.net/?f=%5Cdisplaystyle%20%5Cfrac%7B5%5E%7B2x%7D%7D%7B5%7D%2B5%5E%7Bx%7D5%3D250)
Multiplying by 5:
![5^{2x}+25\cdot5^x=1250](https://tex.z-dn.net/?f=5%5E%7B2x%7D%2B25%5Ccdot5%5Ex%3D1250)
Rearranging:
![5^{2x}+25\cdot5^x-1250=0](https://tex.z-dn.net/?f=5%5E%7B2x%7D%2B25%5Ccdot5%5Ex-1250%3D0)
Recall that:
![5^{2x}=(5^{x})^2](https://tex.z-dn.net/?f=5%5E%7B2x%7D%3D%285%5E%7Bx%7D%29%5E2)
![(5^{x})^2+25\cdot5^x-1250=0](https://tex.z-dn.net/?f=%285%5E%7Bx%7D%29%5E2%2B25%5Ccdot5%5Ex-1250%3D0)
Calling
![y=5^{x}:](https://tex.z-dn.net/?f=y%3D5%5E%7Bx%7D%3A)
![y^2+25y-1250=0](https://tex.z-dn.net/?f=y%5E2%2B25y-1250%3D0)
Factoring:
![(y-25)(y+50)=0](https://tex.z-dn.net/?f=%28y-25%29%28y%2B50%29%3D0)
There are two possible solutions:
y=25
y=-50
Since
![y=5^{x}](https://tex.z-dn.net/?f=y%3D5%5E%7Bx%7D)
y cannot be negative, thus:
![5^{x}=25=5^2](https://tex.z-dn.net/?f=5%5E%7Bx%7D%3D25%3D5%5E2)
The solution is:
x = 2
The answer is [ all real numbers ]
The domain are the input values which makes the function defined and real.
Since we don't have any constraints or any undefined points, the domain could be literally anything. Thus proves out answer.
Best of Luck!
Answer:
Step-by-step explanation:
1). Equation of a line which has slope 'm' and y-intercept as 'b' is,
y = mx + b
If slope 'm' = 1 and y-intercept 'b' = -3
Equation of the line will be,
y = x - 3
x - y = 3
2). Equation of a line having slope 'm' and passing through a point (x', y') is,
y - y' = m(x - x')
If the slope 'm' = 1 and point is (-1, 2),
The the equation of the line will be,
y - 2 = 1(x + 1)
y = x + 1 + 2
y = x + 3
x - y = -3
3). Equation of a line passing through two points
and
will be,
![y-y_1=\frac{(y_2-y_1)}{(x_2-x_1)}(x-x_1)](https://tex.z-dn.net/?f=y-y_1%3D%5Cfrac%7B%28y_2-y_1%29%7D%7B%28x_2-x_1%29%7D%28x-x_1%29)
If this line passes through (-2, 3) and (-3, 4),
![y-3=\frac{(4-3)}{(-3+2)}(x+2)](https://tex.z-dn.net/?f=y-3%3D%5Cfrac%7B%284-3%29%7D%7B%28-3%2B2%29%7D%28x%2B2%29)
y - 3 = -1(x + 2)
y = -x - 2 + 3
y = -x + 1
x + y = 1