Solve the systems below:
1. x + 7y = 0
2x - 8y = 22
2. x-y=3
7x - y=-3
3.-9 + 5y = -4x
-11x = -20+9y
4. y = 4x - 9
y=x-3
Tell which method you used to solve each system and why you chose
that method

Check my explanation

Step-by-step explanation:

1. x=-7y

2(-7y)-8y=22

-14y-8y=22

-22y=22

y=-1;x=7, I used subtitution because that process was easier.

2. x=3+y

7(3+y)-y=-3

21+7y-y=-3

21+6y=-3

6y=-24

y=-4; x=-1, I used subtitution because that process was easier.

3. x=1 and y=1, I used elimination because that process was easier.

4. x-3=4x-9

-3x=-6

x=3; y=0, I used subsitution because that process was easier.

56.6

step-by-step explanation:

the ratio of the perimeters is equal to the scale.

the ratio of the areas is equal to the square of the scale.

34 / 20 = k

a / 19.6 = k²

substituting:

a / 19.6 = (34 / 20)²

a = 19.6 (34 / 20)²

a ≈ 56.6