Answer:
Multiplication property of equality:
If a = b then,
![a * c = b * c](https://img.qammunity.org/2020/formulas/mathematics/middle-school/xruinkwu5an4v1pejapxh4gvd0f5yg0yvy.png)
Addition property of equality:
If a = b then;
![a+c = b+c](https://img.qammunity.org/2020/formulas/mathematics/high-school/jz5qllltp3gbyesdm29zt2vlc81ftr3oky.png)
Subtraction property of equality:
If a = b then;
![a-c = b-c](https://img.qammunity.org/2020/formulas/mathematics/high-school/ap473uezl77i9ne3kehjttmhqzwquxgu1n.png)
Division property of equality:
If a = b then;
![(a)/(c) = (b)/(c)](https://img.qammunity.org/2020/formulas/mathematics/high-school/tiy4am88hjuyy00ugurgzm73qiowpcz8tw.png)
Substitution Property of equality:
if a = b then a can be substituted in b , and b can be substituted in a.
Given the system of equation:
.....[1]
......[2]
Using multiplication property of equality
Multiply by 2 in equation [1] both sides we get;
.....[3]
Using addition property of equality:
Add equation [2] and [3] to eliminate y we have;
![8x = 24](https://img.qammunity.org/2020/formulas/mathematics/high-school/35zs7pvrbtm3dz534htv5v20xgeglpj3vr.png)
Using Division property of equality:
Divide by 8 to both sides of an equation we have;
x = 3
Using substitution property of equality:
Substitute the value of x in equation [1] we have;
![3(3)-4y =9](https://img.qammunity.org/2020/formulas/mathematics/high-school/7h2ns5ahw6nogc2ocik1rg4psla1hh5c3x.png)
9-4y = 9
Using subtraction property of equality:
Subtract 9 from both sides we get;
-4y = 0
Divide by 4 to both sides we get;
y = 0