I only know the substitutional method so I am going to give you the answers.
1. (remember I am only using the substitutional method, I am doing the method wrong...)
x + y = 10, 3x - y = 2, 5(3x-y) = 5(2), 15x - 5y = 10, 15x -5y = x + y, 14x = 6y, x = 3/7 y , 3/7 y + y = 10, 10/7y = 10, 10 y = 70, y = 7, 14x = 42. x =3
y = 7, x = 3
2. What I know:
x + y = 6
x + 2x = 6
3x = 6
x = 2, y =4
3. I am using a video to help me remember.
x = 2y + 3 2x + 3y = -3.
-3 = 2y - x -3 = 3y + 2x
0 = - y + 3x, y = 3x
x = 2(3x) + 3, x = 6x + 3
-5x = 3, x = -3/5
y = 3(-3/5)
y = -9/5, x = -3/5
right E units, down A units
whenever you have ( -E) whatever you have Inside you do the opposite just like this problem. We have -E so to the right. if it was positive we go left
Since multiplying by 0.5 is the same as dividing by 2, the problem is described by the sentence
"Half the sum of a number and 40 equals 200"
(-3, -3) and (2, 7).
The solutions to a graphed system of equations are where the two graphs cross each other. So in this case the two equations cross at (-3, -3) and (2, 7), and those points are the solutions to the system of equations.
