First thing you should do is reduce coefficients.
1st equation has all multiples of '2'. Divide by 2
---> x +3y = -6
2nd equation has multiples of 5. Divide by 5.
---> x - y = 2
Now elimination part is easier.
Eliminate 'x' variable by subtracting 2nd equation from 1st.
x + 3y = -6
-(x - y = 2)
----------------------
4y = -8
Solve for 'y'
4y = -8
y = (-8)/4 = -2
Substitute value for 'y' back into 2nd equation:
x - (-2) = 2
x + 2 = 2
x = 0
Solution to system is:
x=0, y =-2
Answer: 
Step-by-step explanation:
Properties of logarithm:
Consider,
![2\log x-\log y+2 \log z\\\\ =\log x^2-\log y+\log z^2\ \ \ \ \text{[By (i)]}\\\\= \log x^2+\log z^2-\log y\\\\=\log(x^2z^2)-\log y\ \ \ \ [\text{By } (ii) ]\\\\=\log(\dfrac{x^2z^2}{y}) \ \ \ \ [\text{By (iii)}]](https://tex.z-dn.net/?f=2%5Clog%20x-%5Clog%20y%2B2%20%5Clog%20z%5C%5C%5C%5C%20%3D%5Clog%20x%5E2-%5Clog%20y%2B%5Clog%20z%5E2%5C%20%5C%20%5C%20%5C%20%5Ctext%7B%5BBy%20%28i%29%5D%7D%5C%5C%5C%5C%3D%20%5Clog%20x%5E2%2B%5Clog%20z%5E2-%5Clog%20y%5C%5C%5C%5C%3D%5Clog%28x%5E2z%5E2%29-%5Clog%20y%5C%20%5C%20%5C%20%5C%20%5B%5Ctext%7BBy%20%7D%20%28ii%29%20%5D%5C%5C%5C%5C%3D%5Clog%28%5Cdfrac%7Bx%5E2z%5E2%7D%7By%7D%29%20%20%20%20%5C%20%5C%20%5C%20%5C%20%5B%5Ctext%7BBy%20%28iii%29%7D%5D)
Which one is prime number 2, 3, 5, 7, 13, 14, 15, 23, 25, 29, 30, 36, 61
soldier1979 [14.2K]
2,3,5,7,13,15,23,and 61 are all prime
Answer:
65
because 22 + 63 equals 85 and 20+65 equals 85 as well.
hope it helps :)
