How do you solve the system 1/3 x - 1/12 y = -713x112y=7 and 1/3 x + 1/6 y = 1113x+16y=11?

2 Answers

x = -3 and y = 72

Explanation:

So we are given with 22 equations

equation 1 is 1/3x - 1/12y13x112y = -7

equation 2 is 1/3x + 1/6y13x+16y = 11

equation 1 can be written as 4x - y = -84 4xy=84
(multiplied the whole equation by 12)

equation 2 can be written as 2x + y = 662x+y=66
(multiplied whole equation by 6)

now we add both the equations

==> 4x - y + 2x + y = -84 + 664xy+2x+y=84+66
==> 6x = -186x=18

==> x = -18/6x=186

==> x = -3x=3

now we substitute x = -3x=3 in any one of the equations
we will get y = 72y=72

Mar 19, 2018

x = -3 and y =72x=3andy=72

Explanation:

Both equations have the same xx- coeffiecients.

Rewrite both equations:

1/3x = 1/12y -7" "and" "1/3x= -1/6y +1113x=112y7 and 13x=16y+11

1/3x = 1/3x13x=13x , so equate the right sides of the equations.

1/12y -7 = -1/6y +11" "larr112y7=16y+11 multiply by 1212

y-84 = -2y+132y84=2y+132

y +2y = 132+84y+2y=132+84

3y = 2163y=216

y = 72y=72

Substitute to find xx

1/3x = 1/12 (72)-713x=112(72)7

1/3x = 6-713x=67

1/3x = -113x=1

x =-3x=3