# SOLVING LINEAR EQUATIONS EQUATIONS AND SOLUTIONS EQUATIONS ARE

- Slides: 38

SOLVING LINEAR EQUATIONS

EQUATIONS AND SOLUTIONS • EQUATIONS ARE MATHEMATICAL STATEMENTS THAT SAY TWO EXPRESSIONS ARE EQUAL. • SOLUTIONS ARE VALUES OF THE VARIABLES THAT MAKE THE EQUATION TRUE (ANSWERS).

SOLVING EQUATIONS • TO SOLVE AN EQUATION IS TO FIND A SOLUTION, YOU MUST FIRST ISOLATE THE VARIABLE. • TO ISOLATE THE VARIABLE, YOU MUST USE THE INVERSE OF THE OPERATION TO “UNDO” THE CURRENT OPERATION. MAKE SURE YOU PERFORM THE SAME OPERATION ON BOTH

ADDITION PROPERTY OF EQUALITY

EXAMPLES • SOLVE EACH EQUATION. • X – 10 =4

EXAMPLES • SOLVE EACH EQUATION. • X – 10 = 4 (EQUATION) • X – 10 + 10 = 4 + 10 • X = 14 (SOLUTION)

EXAMPLES • SOLVE EACH EQUATION. • M – 48 = 29

EXAMPLES • SOLVE EACH EQUATION. • M – 48 = 29 (EQUATION) • M – 48 + 48 = 29 + 48 • M = 77 (SOLUTION)

SUBTRACTION PROPERTY OF EQUALITY

EXAMPLES • SOLVE EACH EQUATION. • X + 7 = 9

EXAMPLES • SOLVE EACH EQUATION. • X + 7 = 9 (EQUATION) • X + 7 – 7 = 9 – 7 • X = 2 (SOLUTION)

EXAMPLES • SOLVE EACH EQUATION. • 21 + Q = -18

EXAMPLES • SOLVE EACH EQUATION. • 21 + Q = -18 (EQUATION) • 21 – 21 + Q = -18 – 21 • Q = -39 (SOLUTION)

MULTIPLICATION PROPERTY OF EQUALITY

EXAMPLES • SOLVE EACH EQUATION. • (P/5) = 10

EXAMPLES • SOLVE EACH EQUATION. • (P/5) = 10 (EQUATION) • (P/5) * 5 = 10 * 5 • P = 50 (SOLUTION)

EXAMPLES • SOLVE EACH EQUATION. • 18 = (W/2)

EXAMPLES • SOLVE EACH EQUATION. • 18 = (W/2) (EQUATION) • 18 * 2= (W/2) * 2 • W = 36 (SOLUTION)

DIVISION PROPERTY OF EQUALITY

EXAMPLES • SOLVE EACH EQUATION. • 7 X = 56

EXAMPLES • SOLVE EACH EQUATION. • 7 X = 56 (EQUATION) • 7 X / 7 = 56 / 7 • X = 8 (SOLUTION)

EXAMPLES • SOLVE EACH EQUATION. • 84 = 3 B

EXAMPLES • SOLVE EACH EQUATION. • 84 = 3 B (EQUATION) • 84 / 3 = 3 B / 3 • X = 28 (SOLUTION)

MORE PROPERTIES OF EQUALITY

MULTI-STEP EQUATIONS • MULTI-STEP EQUATIONS ARE EQUATIONS WITH MORE THAN ONE OPERATION AND THEREFORE REQUIRE MORE THAN ONE STEP TO SOLVE. IDENTIFY THE OPERATIONS IN THE EQUATION AND THE ORDER IN WHICH THEY ARE APPLIED TO THE VARIABLE. THEN USE INVERSE OPERATIONS AND WORK BACKWARD TO UNDO THEM ONE AT A TIME.

EXAMPLES • SOLVE 10 = 6 – 2 X.

EXAMPLES • SOLVE 10 = 6 – 2 X. • 10 = 6 – 2 X ADDED. FIRST X IS MULTIPLIED BY -2. THEN 6 IS • 10 – 6 = 6 – 2 X BOTH SIDES. WORK BACKWARD: SUBTRACT 6 FROM • 4 = – 2 X SIDES SINCE X IS MULTIPLIED BY – 2, DIVIDE BOTH • 4 / -2 = -2 X / -2 BY -2 TO UNDO THE MULTIPLICATION. • -2 = X

EXAMPLES • SOLVE 1. 5 = 1. 2 Y – 5. 7.

EXAMPLES • SOLVE 1. 5 = 1. 2 Y – 5. 7. • 1. 5 = 1. 2 Y – 5. 7 SUBTRACTED. FIRST Y IS MULTIPLIED BY 1. 2. THEN 5. 7 IS • 1. 5 + 5. 7 = 1. 2 Y – 5. 7 + 5. 7 WORK BACKWARD: ADD 5. 7 TO BOTH SIDES. • 7. 2 = 1. 2 Y SINCE Y IS MULTIPLIED BY 1. 2, DIVIDE BOTH SIDES • 7. 2 / 1. 2 = 1. 2 Y / 1. 2 BY 1. 2 TO UNDO THE MULTIPLICATION. • 6=Y

MULTI-STEP EQUATIONS THAT HAVE FRACTIONS • WHEN SOLVING EQUATIONS THAT CONTAIN FRACTIONS, MULTIPLY EVERY TERM BY THE LEAST COMMON DENOMINATOR TO CLEAR THE FRACTIONS.

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SOLVING EQUATIONS WITH VARIABLES ON EACH SIDE • TO SOLVE AN EQUATION WITH VARIABLES ON EACH SIDE OF THE EQUAL SIGN, SIMPLIFY EACH SIDE, THEN USE INVERSE OPERATIONS TO GROUP VARIABLES ON ONE SIDE AND NUMBERS ON THE OPPOSITE SIDE. LAST, ISOLATE THE VARIABLE.

EXAMPLES • SOLVE 6 Y + 21 + 7 = 4 Y – 20 + 5 Y

EXAMPLES • SOLVE 6 Y + 21 + 7 = 4 Y – 20 + 5 Y • 6 Y + 21 + 7 = 4 Y – 20 + 5 Y ORIGINAL EQUATION • 6 Y + 28 = 9 Y – 20 SIMPLIFY • 6 Y – 6 Y + 28 = 9 Y – 6 Y – 20 SUBTRACTION PROPERTY • 28 = 3 Y – 20 SIMPLIFY • 28 + 20 = 3 Y – 20 + 20 ADDITION PROPERTY • 48 = 3 Y SIMPLIFY • 48 / 3 = 3 Y / 3 • 16 = Y DIVISION PROPERTY SOLUTION

EXAMPLES • SOLVE 3(W + 7) – 5 W = W + 12

EXAMPLES • SOLVE 3(W + 7) – 5 W = W + 12 • 3(W + 7) – 5 W = W + 12 ORIGINAL EQUATION • 3 W + 21 – 5 W = W + 12 DISTRIBUTIVE PROPERTY • -2 W + 21 = W + 12 SIMPLIFY • -2 W + 21 = W + 2 W + 12 ADDITION PROPERTY • 21 = 3 W + 12 SIMPLIFY • 21 - 12 = 3 W + 12 – 12 SUBTRACTION PROPERTY • 9 = 3 W SIMPLIFY • 9 / 3= 3 W / 3 DIVISION PROPERTY • 3 = W SOLUTION