To solve an equation… :
To solve an equation… Think of an equation as two sides with an equal sign in the middle:
3 + (2 x n) = 13 ?Remember your goal:
Get the variable on one side of the equal sign and the numbers on the other.
?Remember 1 rule:
To maintain equality, whatever you do to one side, do the same thing to the other. 3 + (2 x n) = 13 (3-3) + (2 x n) = 13-3 2 x n = 10 2÷2 x n = 10÷2 1 x n = 5 n = 5 Subtract 3 Divide by 2 Subtract 3 Divide by 2 When solving equations,
To solve another equation… :
To solve another equation… 4d – 7 = 13 Remember your goal:
Get the variable on one side of the equal sign and the numbers on the other.
Remember 1 rule:
To maintain the equality, whatever you do to one side, do the same thing to the other. 4d – 7 = 13 4d - 7 + 7 = 13 + 7 4d – 0 = 20 4d = 20 4d ÷ 4 = 20 ÷ 4 d = 5 Add 7 Divide by 4 Add 7 Divide by 4 Remember the invisible multiplication sign located in here: 4 x d – 7 = 13
Always check your solution… :
Always check your solution… 3 + (2 x n) = 13 Check: n = 5 3 + (2 x 5) = 13 4d – 7 = 13 Check: d = 5 4x5 – 7 = 13 13 = 13 ? 13 = 13 ? …to be sure that it creates an equality!
Expressions :
Expressions “Expressions” are similar to equations, but there is ONE important difference:
EXPRESSIONS do NOT have an equal sign in them. Expression:
4n + 5 Equation:
4n + 5 = 33 You evaluate an expression. You solve an equation. Instructions,
Evaluate the following expression if n=3:
4n + 5
4x3 + 5
17 Instructions,
Solve the following equation:
4n + 5 = 33 4n + 5 – 5 = 33 – 5
4n + 0 = 28
4n = 28
n =7 Check!! does 4x7+5 = 33 ??