What is the solution for 2x + y = 52x+y=5 and 2x - 5y = 12x5y=1?

1 Answer
Feb 25, 2017

See the entire solution process below:

Explanation:

Step 1) Solve the first equation for yy:

2x + y = 52x+y=5

2x - color(red)(2x) + y = 5 - color(red)(2x)2x2x+y=52x

0 + y = 5 - 2x0+y=52x

y = 5 - 2xy=52x

Step 2) Substitute 5 - 2x52x for yy in the second equation and solve for xx:

2x - 5y = 12x5y=1 becomes:

2x - 5(5 - 2x) = 12x5(52x)=1

2x - 25 + 10x = 12x25+10x=1

12x - 25 = 112x25=1

12x - 25 + color(red)(25) = 1 + color(red)(25)12x25+25=1+25

12x - 0 = 2612x0=26

12x = 2612x=26

(12x)/color(red)(12) = 26/color(red)(12)12x12=2612

(color(red)(cancel(color(black)(12)))x)/cancel(color(red)(12)) = 13/6

x = 13/6

Step 3) Substitute 13/6 for x in the solution to the first equation at the end of Step 1 and calculate y:

y = 5 - 2x becomes:

y = 5 - (2 xx 13/6)

y = 5 - 26/6

y = (6/6 xx 5) - 26/6

y = 30/6 - 26/6

y = 4/6

y = 2/3

The solution is x = 13/6 and y = 2/3 or (13/6, 2/3)