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Patterns and Algebra - Solving One-Step Equations

Grade 6IB

Review the key concepts, formulae, and examples before starting your quiz.

๐Ÿ”‘Concepts

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An algebraic equation is a mathematical statement showing that two expressions are equal, represented by the equals sign (==). Think of it like a balanced scale where both sides must have the same total value to remain level.

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A variable is a letter, such as xx or nn, that represents an unknown number we are trying to find. The goal of solving a one-step equation is to isolate the variable on one side of the equals sign.

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Inverse operations are 'opposite' operations that undo each other. Addition (++) and subtraction (โˆ’-) are inverse operations, while multiplication (ร—\times) and division (รท\div) are inverse operations.

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The Golden Rule of Algebra states that to keep an equation balanced, whatever operation you perform on one side of the equals sign, you must perform the exact same operation on the other side. If you visualize a balance scale, adding 55kg to one side requires adding 55kg to the other to maintain equilibrium.

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To solve an addition equation like x+5=12x + 5 = 12, you use the inverse operation of subtraction. You subtract 55 from both sides to find that x=7x = 7.

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To solve a subtraction equation like xโˆ’8=10x - 8 = 10, you use the inverse operation of addition. You add 88 to both sides to find that x=18x = 18.

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To solve a multiplication equation like 3x=153x = 15, you use the inverse operation of division. By dividing both sides by 33, you isolate the variable to find x=5x = 5.

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To solve a division equation like x4=6\frac{x}{4} = 6, you use the inverse operation of multiplication. Multiplying both sides by 44 cancels out the division and reveals that x=24x = 24.

๐Ÿ“Formulae

Addition Equation: x+a=bโ€…โ€ŠโŸนโ€…โ€Šx=bโˆ’ax + a = b \implies x = b - a

Subtraction Equation: xโˆ’a=bโ€…โ€ŠโŸนโ€…โ€Šx=b+ax - a = b \implies x = b + a

Multiplication Equation: ax=bโ€…โ€ŠโŸนโ€…โ€Šx=baax = b \implies x = \frac{b}{a}

Division Equation: xa=bโ€…โ€ŠโŸนโ€…โ€Šx=bร—a\frac{x}{a} = b \implies x = b \times a

Verification: Substitute the value of xx back into the original equation to check if LHS=RHSLHS = RHS (Left Hand Side = Right Hand Side).

๐Ÿ’กExamples

Problem 1:

Solve for mm: mโˆ’14=30m - 14 = 30

Solution:

mโˆ’14+14=30+14m - 14 + 14 = 30 + 14 m=44m = 44

Explanation:

To isolate the variable mm, identify the operation being performed on it, which is subtraction of 1414. Apply the inverse operation by adding 1414 to both sides of the equation to maintain balance. The โˆ’14-14 and +14+14 on the left cancel out, leaving m=44m = 44.

Problem 2:

Solve for yy: 7y=567y = 56

Solution:

7y7=567\frac{7y}{7} = \frac{56}{7} y=8y = 8

Explanation:

In the expression 7y7y, the variable yy is being multiplied by 77. To undo this multiplication and isolate yy, divide both sides of the equation by 77. This simplifies the left side to 1y1y (or just yy) and the right side to 88.