2 Fill in the blanks
A system of equations and its solution are given below.
System A
I - y = 7
-3. + 9y = -39
Solution: (4, -3)
Complete the sentences to explain what steps were followed to obtain the system of equations below.
System B
I - y = 7
by = -18
times the
To get system B, the
equation in system A was replaced by the sum of that equation and
equation. The solution to system B the same as the solution to system A.
Reset
Next
tum. All rights reserved.

step-by-step explanation:

i need to answer questions so i dont know but i think its the first one because it goes up but a consent rate

(b) 240

step-by-step explanation:

first, we use the pythagorean formula using the given side lengths to find x. then we use x to find the side lengths. then we add the side lengths to find the perimeter.

pythagorean theorem formula:

a^2 + b^2 = c^2

(x - 20)^2 + (x - 40)^2 = x^2

x^2 - 40x + 400 + x^2 - 80x + 1600 = x^2

x^2 -120x + 2000 = 0

(x - 100)(x - 20) = 0

x - 100 = 0 or x - 20 = 0

x = 100 or x = 20

we see that the solution x = 20 must be discarded because it will give a negative side length and a side length of 0. the only valid solution is x = 100.

perimeter = sum of the lengths of the sides

perimeter = x + x - 20 + x - 40

perimeter = 3x - 60

replace x with 100.

perimeter = 3(100) - 60

perimeter = 300 - 60

perimeter = 240