How do you solve the following system: 7y − 6x − 5 = 0, -5x − y = 14 7y6x5=0,5xy=14?

1 Answer
May 30, 2018

See a solution process below:

Explanation:

Step 1) Solve the second equation for yy:

-5x - y = 145xy=14

-5x - color(blue)(14) - y + color(red)(y) = 14 - color(blue)(14) + color(red)(y)5x14y+y=1414+y

-5x - 14 - 0 = 0 + y5x140=0+y

-5x - 14 = y5x14=y

y = -5x - 14y=5x14

Step 2) Substitute (-5x - 14)(5x14) for yy in the first equation and solve for xx:

7y - 6x - 5 = 07y6x5=0 becomes:

7(-5x - 14) - 6x - 5 = 07(5x14)6x5=0

-(7 xx 5x) - (7 xx 14) - 6x - 5 = 0(7×5x)(7×14)6x5=0

-35x - 98 - 6x - 5 = 035x986x5=0

-35x - 6x - 98 - 5 = 035x6x985=0

(-35 - 6)x - 103 = 0(356)x103=0

-41x - 103 = 041x103=0

-41x - 103 + color(red)(103) = 0 + color(red)(103)41x103+103=0+103

-41x - 0 = 10341x0=103

-41x = 10341x=103

(-41x)/color(red)(-41) = 103/color(red)(-41)41x41=10341

(-color(red)(cancel(color(black)(41)))x)/cancel(color(red)(-41)) = -103/41

x = -103/41

Step 3) Substitute -103/41 for x in the solution to the second equation at the end of Step 1 and calculate y:

y = -5x - 14 becomes:

y = (-5 xx -103/41) - 14

y = 515/41 - (41/41 xx 14)

y = 515/41 - 574/41

y = -59/41

The Solution Is:

x = -103/41 and y = -59/41

Or

(-103/41, -59/41)