2 Why do we do the same thing to both sides of an equation Discuss that you must keep it balanced. If I give one daughter 20 dollars then I need to give the other daughter 20 dollars.If I give the left side of the room 5 points on a test I need to give the right side of the room 5 points.
3 Why do we do the same thing to both sides of an equation
4 Think of this equation as a balance scale. Ex. 1) Solve r + 16 = -7Think of this equation as a balance scale.r + 16-7=Whatever you do to one side has to be done to the other to keep it balanced!
5 1) Solve r + 16 = -7To solve, you must get the variable by itself. What number is on the same side as r? 16 To get r by itself, we must undo the “add 16”. What is the opposite of addition? Subtract 16
9 2) Solve x + 2 = -3x = -5= -3Draw “the river” to separate the equation into 2 sidesSubtract 2 from both sidesSimplify verticallyCheck your answer by substituting your answer back into the problemOn homework and tests, be sure to check your work!!There is no reason why you should miss a problem!
10 Addition and subtraction Properties of Equality Definition: Either adding or subtracting the same number to each side of the equation produces an equivalent equation.Example:X - 9 = 15How can you check your answers?
11 Try These: Don’t forget to check your answer m + 17 = 3b – (-4) = 9
15 Multiplication and Division Properties of Equality Definition: If you multiply or divide each side of the equation by the same nonzero number you produce an equivalent equation. Example 6: Multiplication: