Solve, using the substitution method. X + y = -11 2x - 3y = 3
A. (-6, -5)
B. (-10, -1)
C. (15, -4)
D. (6, 1)

A. (-6,-5)

Step-by-step explanation:

A: Correct because -6+-5=-11True

    and 2(-6)-3(-5) is equal to -12-(-15) and a - plus a - equals a +

    so our new equation is -12+15=3True

  -Your welcome and I hope this helps you, please rate 5 stars =D

(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

something over 10 so ? /10

step-by-step explanation: