Answer:
D.(2,-1,-1)
Step-by-step explanation:
-a+4b+2c=-8
3a+b-4c=9
b = -1
Substitute b=-1 into the other equations
-a -4 +2c = -8
3a -1 -4c =9
Multiply the first equation by 2 so we can eliminate c
-2a -8 +4c = -16
Add this to the second equation
-2a -8 +4c = -16
3a -1 -4c =9
-----------------
a -9 = -7
Add 9 to each side
a-9+9 = -7+9
a =2
b=-1
Now we need to find c
-a +4b +2c = -8
-2 -4 +2c = -8
-6+2c = -8
Add 6 to each side
-6+6 +2c = -8+6
2c = -2
Divide by 2
2c/2 = -2/2
c=-1
(2,-1,-1)
Answer:
12 cm
Step-by-step explanation:
This would be the cubic root of 1728
= 12 cm
( 1729 is known as Ramanajan's number. Look it up - it's interesting)
Answer:
Step-by-step explanation:
The expression to transform is:
![(\sqrt[6]{x^5})^7](https://tex.z-dn.net/?f=%28%5Csqrt%5B6%5D%7Bx%5E5%7D%29%5E7)
Let's work first on the inside of the parenthesis.
Recall that the n-root of an expression can be written as a fractional exponent of the expression as follows:
![\sqrt[n]{a} = a^{\frac{1}{n}}](https://tex.z-dn.net/?f=%5Csqrt%5Bn%5D%7Ba%7D%20%3D%20a%5E%7B%5Cfrac%7B1%7D%7Bn%7D%7D)
Therefore ![\sqrt[6]{a} = a^{\frac{1}{6}}](https://tex.z-dn.net/?f=%5Csqrt%5B6%5D%7Ba%7D%20%3D%20a%5E%7B%5Cfrac%7B1%7D%7B6%7D%7D)
Now let's replace 
with 
which is the algebraic form we are given inside the 6th root:
![\sqrt[6]{x^5} = (x^5)^{\frac{1}{6}}](https://tex.z-dn.net/?f=%5Csqrt%5B6%5D%7Bx%5E5%7D%20%3D%20%28x%5E5%29%5E%7B%5Cfrac%7B1%7D%7B6%7D%7D)
Now use the property that tells us how to proceed when we have "exponent of an exponent":
Therefore we get: 
Finally remember that this expression was raised to the power 7, therefore:
^7=(x^\frac{5}{6})^7=x^\frac{35}{6}](https://tex.z-dn.net/?f=%5Btex%5D%28%5Csqrt%5B6%5D%7Bx%5E5%7D%29%5E7%3D%28x%5E%5Cfrac%7B5%7D%7B6%7D%29%5E7%3Dx%5E%5Cfrac%7B35%7D%7B6%7D)
[/tex]
An use again the property for the exponent of a exponent:
Answer:
Original number 26.
Step-by-step explanation:
xy - two-digit number
1) x + y = 8
2) Original two-digit number can be written as
10*x + y
3) If the digits interchanged yx,
then the new number can be written as
10*y + x
4) Double the original number is
2*(10*x + y)
5) New number is 10 more than double the original number
(10*y + x) - (2*(10*x + y)) = 10
6) Now we have the system of 2 equations:
x + y = 8
(10*y + x) - (2*(10*x + y)) = 10 -----> 10y + x - (20x + 2y) = 10 ---> 8y - 19x = 10
x = 8 - y
8y - 19(8 - y) = 10
8y - 152 +19y = 10
27y = 162
y = 6
x = 8 - y = 8 - 6 = 2
x = 2
So, x =2, y = 6.
Original number 26.
Check:
Original number 26.
New number 62.
Double of the original number = 2*26= 52.
New number is 10 more than double the original number :
62 - 52 = 10 True
