Presentation on theme: "Solving Equations Using Addition and Subtraction"— Presentation transcript:
1 Solving Equations Using Addition and Subtraction Algebra I Section 3.1
2 Think of an equation as having a left and right side Think of an equation as having a left and right side. Each side is on a balanced scalex + 3 = 5x1 1 11 1 11 1If I remove the 3 ones from the left side, how to I keep the scale from tipping?
3 A. Equivalent Equations: equations that have the same solution. Example:x + 3 = 5x = 5 – 3x = 2
4 B. Isolating a variable: changing an equation to get the variable by itself on one side of the equation.Example: x – 2 + (-4) = 12x = 12 –To isolate a variable, use inverse operationsInverse Operations: Operations that undo each other. The inverse of addition is ________________. The inverse of multiplication is ______________.
5 x – 2 = 6 x + 5 = 7 x = 8+3 6 = x Ways to Isolate a Variable a. Add a number to both sidesx – 2 = 6b. Subtract a number from both sidesx + 5 = 7c. Simplifyx = 8+3d. Change sides6 = x
6 C. Solution Steps: each step you take to isolate a variable C. Solution Steps: each step you take to isolate a variable. (you must show these)Examples:State the inverse operationsAdd 28Subtract 15
7 Solve the equation (Show solution steps) X = 4 – 7t – 2 = 6-9 = 2 + y
10 4 = -b – 12-r – (-7) = 16Write an equation to represent the following problem. There are 15 members of a high school band brass section. After graduation there are only 7 members. How many members graduated?