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
Srinivas
Sep 16, 2015

#x = 2 and y = 3#

Explanation:

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

Gió
Sep 16, 2015

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

Explanation:

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

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