How do you solve this system of equations: -3x - 3y = 0 and - 3x - 10y = 143x3y=0and3x10y=14?

3 Answers
Dec 14, 2017

x=2x=2 and y=-2y=2

Explanation:

As -3x-3y=03x3y=0, -3x=3y3x=3y

Putting this in -3x-10y=143x10y=14 we get

3y-10y=143y10y=14

or -7y=147y=14

or y=14/(-7)=-2y=147=2

and -3x=3×(-2)3x=3×(2)

or -3x=-63x=6

or x=(-6)/(-3)=2x=63=2

Hence x=2x=2 and y=-2y=2

Dec 14, 2017

x = 2 and y = -2

Explanation:

Given:

-3x - 3y = 0 and -3x - 10y = 143x3y=0and3x10y=14

Let -3x = 3y 3x=3y
Now, we substitute for -3x3x in -3x - 10y = 143x10y=14, that is;

3y - 10y = 143y10y=14
-7y = 147y=14
color(red)(y = -2)y=2

Next, substitute the value of y in any one of the above equations to get the respective x value;

-3x - 10(-2) = 143x10(2)=14
-3x + 20 = 143x+20=14
-3x = -63x=6
color(red)(x = 2) x=2

Therefore, x = 2x=2 and y = -2.y=2.

Dec 14, 2017

x=2 and y=-2x=2andy=2

Explanation:

Note that the terms in xx are the same in each equation.

Isolate the xx term, make it the subject in each equation.

-3x = 3y" "and" " -3x = 10y+143x=3y and 3x=10y+14

We know that -3x =-3x3x=3x, so equating the right sides gives:

10y +14 = 3y" "larr10y+14=3y now solve for yy

10y -3y = -1410y3y=14

7y = -147y=14

y =-2y=2

Use the value of yy to find xx

-3x = 3(-2)3x=3(2)

-3x = -63x=6

x =2x=2

Check in the second equation.

-3x = 10y+143x=10y+14

-3(2)" "and" "10(-2)+143(2) and 10(2)+14

-6" " and " "-20+146 and 20+14

-6=-66=6