We want to keep equations balanced so that the two sides of the equals sign remain equivalent. If we don't we could change what the equation means. Think of a balanced set of scales. The scale remains level when the weights on both side of the scales are even. The same thing happens with equations.
This shows a balanced equation.
If we add a weight to one side and not to the other, then the scales will no longer be balanced.
Beginning with the equation $$x=8, write the new equation produced by adding 2 to both sides.
Think:
Do: $$x+2=10
Beginning with the equation $$x=−99, write the new equation produced by dividing both sides by 11.
Think:
Do: $$x11=−9
Beginning with the equation $$33x=99, write the new equation produced by dividing both sides by 11.
Think: Just like before, we need to divide both the left and right side of the equation by 11.
Do: $$3x=9
Beginning with the equation $$x=14, write the equation produced by subtracting $$7 from both sides.
Beginning with the equation $$x=99, write the equation produced by dividing both sides by $$11.
Keep equations balanced by always performing the exact same operation to both sides of the equation.