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

3 Answers
Dec 14, 2017

x=2 and y=-2

Explanation:

As -3x-3y=0, -3x=3y

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

3y-10y=14

or -7y=14

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

and -3x=3×(-2)

or -3x=-6

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

Hence x=2 and y=-2

Dec 14, 2017

x = 2 and y = -2

Explanation:

Given:

-3x - 3y = 0 and -3x - 10y = 14

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

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

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

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

Therefore, x = 2 and y = -2.

Dec 14, 2017

x=2 and y=-2

Explanation:

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

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

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

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

10y +14 = 3y" "larr now solve for y

10y -3y = -14

7y = -14

y =-2

Use the value of y to find x

-3x = 3(-2)

-3x = -6

x =2

Check in the second equation.

-3x = 10y+14

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

-6" " and " "-20+14

-6=-6