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• To get rid of a number in addition from one side, subtract the same number from both sides of equal sign.
• To get rid of a number in subtraction from one side, add the same number both sides of equal sign.
• To get rid of a number in multiplication from one side, divide the same number from both sides of equal sign.
• To get rid of a number in division from one side, multiply the same number both sides of equal sign.

Rules of Addition/ Subtraction:

• Two numbers with similar sign always get added and the resulting number will carry the similar sign.
• Two numbers with opposite signs always get subtracted and the resulting number will carry the sign of larger number.

Rules of Multiplication/ Division:

• The product/quotient of two similarsign numbers is always positive.
• The product/quotient of two numbers with opposite signs is always negative.

In order to solve the given equation$x+y=5$for the variable, isolate the variable term $y$on one side by performing some basic algebraic operations to get rid of the other numbers and terms associated with it.

Here to isolate$y$on both sides, first, subtract $x$ from both sides and then simplify furtheras shown below,

$$\begin{gathered} x+y=5 \\ x+y−x=5−x \end{gathered}$$

Simplify the equation and get,

$$\begin{gathered} x+y=5 \\ x+y−x=5−x \\ y=5−x \end{gathered}$$