Answer:
1) Multiplication property of equality.
2) Subtraction property of equality
3) Division property of equality.
4) Substitution property of equality
5) Simplify
6) Subtraction property of equality
7) Division property of equality
Explanation:
1.) System of linear equation obtain by multiply first equation both the sides by '3' and second equation by '2':
![\left \{ {{6x-12y=54} \atop{6x+6y=0}} \right.](https://img.qammunity.org/2019/formulas/mathematics/middle-school/leccm7l22xb09tav021ufre5ubw8xrbjzq.png)
so, here we get this step by Multiplication property of equality.
2.) -18y=54
we get this step by subtracting the equation second from first
so, here we get this step by Subtraction property of equality.
3.) y = -3
we get this step by dividing -18y=54 by '-18'
so, here we get this step by Division property of equality.
4.) 2x - 4(-3) = 18
Now we substitute the value of y = -3 in equation 2x - 4y = 18
so, here we get this step by Substitution property of equality.
5.) 2x +12 =18
Multiply -4 with -3 so, we get 12
so, here we get this step by Simplify.
6.) 2x = 6
subtract both the sides of 2x +12 =18 by '12'
so, it is solve by Subtraction property of equality.
7.) x = 3
divide both the sides of 2x = 6 by '2'
so, here we get this step by Division property of equality.