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.
She can cut 4 pieces from the ribbon.
-20+14m=10m+16
-10m. -10m
-20+4m=16
+20. +20
4m=36
/4. /4
m=9
We know that
for <span>a Square Pyramid
</span>[lateral area]=4*[a*s/2]--------> 2aS
where
a is the length side of the square base
S is the <span>slant height
</span>a=145 ft
S=856.1 ft
[lateral area]=2*145*856.1---------> 248269 ft²
the answer is 248269 ft²