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Learn to solve equations by undoing operations on variables. Keep equations balanced by applying inverse operations. Practice solving equations step-by-step. Recognize and simplify equations involving fractions, parentheses, and like terms effectively.
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SOLVING EQUATIONS• The single most important skill in algebra• Goal: Find the one value of the variable that makes the sentence true.
For instance, if 2x + 3 = 17,then 7 is the only value of x that will make this a true sentence.So x = 7.
• We can solve equations by doing the OPPOSITE of what has been done to the variable in the problem.• If a problem says +, you subtract.• If a problem has multiplication, you divide.
By doing the opposite, we keep the sides of the equation balanced.
As long as you do the SAME thing to both sides of an equation, it will remain balanced.
When you solve equations, you also do the opposite of the order of operations. Add/subtract firstThen divide/multiply
Solve these equations:4a+ 11 = 59-2b + 13 = 55c – 72 = 98-4d + 11 = 47
Solve these equations:4a+ 11 = 59 a = 12-2b + 13 = 5 b = 45c – 72 = 98 c = 34-4d + 11 = 47 d = -9
Solve these equations:5x – 18 = 40 x = 58/5 or 11.62y + 73 = 54 y = -19/2 or -9.5 _-3z + 5 = 1 z = 4/3 or 1.3
Some equations are even easier.n + 4 = 13Just subtract 4 … x = 95x = 35Just divide by 5 … x = 7
Solve 19 – 2x = 104-19 -19-2x = 85 -2 -2 x = -85/2 or -42.5
If you know the basic steps, you can quickly do equations with more difficult numbers using a calculator.
Fractions mean division, so to cancel, we’ll subtract 13 and then multiply by 7. n = 63
Parentheses• Use distributive property first.Like terms• Combine them first.
-7(2x – 11) = 98 -14x + 77 = 98 -14x = 21 x = -3/2 or -1.5
4p + 3– 2p+ 7+5p+ 2 = 177p + 12 = 17 7p = 5 p = 5/7
5(3x + 5) – 3(2x – 1) = 14515x + 25– 6x + 3 = 1459x + 28 = 145
5(3x + 5) – 3(2x – 1) = 145 15x + 25 – 6x + 3 = 145 9x + 28 = 145 9x = 117 x = 13