4.3

1. 4.3 The Multiplication and Division Principal of Equality

2. Solve equations using the multiplication / division principle of equality • Multiplication / Division principle of equality: • Multiplying or dividing both sides of an equation by the same nonzero amount does not affect its solution. To Solve a linear equation in one variable: Simplify both sides of the equation Distribute, clear parentheses, combine like terms Use the addition / subtraction principle of equality so that all variable terms are on one side and all constants (Numbers) are on the other. Then combine like terms.

3. 2n = 10

4. 7x = 21

5. You Try • - 6m = 30 • 5y = 45 • - 2x = 16

6. Solve Equations using both the addition / subtraction and the multiplication / division principles of equality. • Simplify both sides of the equation • Distribute, clear parentheses, combine like terms • Use the addition / subtraction principle of equality so that all variable terms are on one side and all constants (Numbers) are on the other. Then combine like terms. • Use the multiplication / division principle of equality to clear the remaining coefficients.

7. - 2x – 9 = 7

8. 12 = 26 – 7x

9. 7x – 1 = 3x - 21

10. 15 – 2(y – 3) = 6(2y + 5) – 5y

11. You Try • 4x – 1 = - 21 • 9b + 2 = 5b + 26 • 5t + 13 – t = 3 + 6t – 12 • 9 – 5(x + 4) = 7x – (6x + 5)

12. Counter-Rotating Spiral

13. Solve application problems • Area of parallelogram: A = B × H • Perimeter: P = 2l + 2w • Surface Area: SA= 2lw + 2wh + 2lh • Volume of a box: V = lwh • Distance: d = rt • Voltage: V = ir

14. Juanita is driving at a rate of 59 feet per second (about 40 mph). A sign is 177 feet ahead. How much time until she passes the sign?

15. A building code in a certain region requires that upstairs windows have a minimum area of 864 square inches. Doris wants an upstairs window that is 18 inches wide. What must the length be?