Question

Solve the system below using any method: X+2y=1 5x-4y=-23

Answer 1

X+2y=1
2y =1-x
y= (1-x)/2

5x-4y= -23
By substituting the value of y in this equation
5x -4 {(1-2)/2} = -23
5x- 2 +2x = -23
7x= -21
x= -3


Now, let's find the value of y bu putting the value in any othe two equations
I'll use x +2y=1
-3 +2y=1
2y =4
y=2
So, the value of x and y is -3 and 2 respectively.

Answer 2

I'll use substitute method.
x + 2y = 1. (1)
5x - 4y = -23. (2)

from 1,
x = 1 - 2y. (3)
then I'll substitute (3) into 2,
5(1-2y) - 4y = -23. (this way we only need to calculate y, as x is isolated out)
5 - 10y - 4y = -23
5 - 14y = -23
-14y = -28
y = 2

now we can substitute y = 2 back into (3)
x = 1- 2(2)
x = -3
therefore we get that x is -3 and y is 2.