Answer: 14
Step-by-step explanation: The perimeter is all of the side added together. When finding the perimeter of a rectangle the opposing sides have the same value. So the equation would be 2(12) + 2(a) = 52. 12 x 2 is 24. 52- 24 is 28 and youre left with 28 = 2(a). You divide each side by 2 and get 14 = a
Answer:
this is what i think (check photo)
Step-by-step explanation:
Answer:
For the first question
and
For the second question 
Step-by-step explanation:
Given:
1.
x - 3y = 7
3x + 3y = 9
2.
8x+ 3y = 1
4x + 2y = 0
Elimination method :
In the elimination method we need to make the coefficient of x or the coefficient of y same in both the equation so by adding or subtracting we can eliminate the x term or the y term.
Then substitute that values which you will get on eliminating in any equation you will get the corresponding value.
For the first question, the y coefficient is same hence by adding both the equation we can eliminate 3y term. so on solving we get

Now substitute X equal to 4 in equation x -3y = 7 we get

This way we have x is equal to 4 and y is equal to -1 for question number 1.
For the second question, we will make X coefficient same in the second equation that is multiplying by 2 to the equation 4x + 2y = 0 then we get

Now the coefficient of x term become same now we will subtract the two equations that is 8x + 3y = 1 and 8x + 4y =0 we get

Now substitute y equal to -1 in equation 8x +3y = 1 we get

This way we have x is equal to 0.5 and y is equal to -1 for question number 2.
The answer is: 2y^2-20y+12