How do you find the coordinates of the point of intersection for the pair of lines whose equations y=2x-1 and x+2y=8?

2 Answers
Sep 16, 2015

x = 2 and y = 3x=2andy=3

Explanation:

y = 2x - 1y=2x1 . . . .(1)
x + 2y = 8x+2y=8 . . . . (2)
(1) * 2 = 2y = 4x - 2 . . . .(3)
(2) - (3) = x = 8 - 4x + 2
i.e., 4x + x = 5x = 8 + 2 = 104x+x=5x=8+2=10
or x = 10 / 5 = 2x=105=2
y = 2 * 2 - 1 = 3y=221=3

Sep 16, 2015

I found:
x=2x=2
y=3y=3

Explanation:

You can use the value of yy from the first equation and substitute into the second to get:
x+2(color(red)(2x-1))=8x+2(2x1)=8 and solve for xx:
x+4x-2=8x+4x2=8
5x=105x=10
x=10/5=2x=105=2
use this value back into the first equation to find yy:
y=2*2-1=4-1=3y=221=41=3