🎬 Linear equations in one variable · Class 8 maths · 3:07
Linear equations in one variable: Class 8 maths video
Master Class 8 linear equations in one variable with Captain Calc. Learn balancing equations, solving variables on both sides, and solving real-life word problems easily.
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0:00 Class 8 maths. Linear equations in one variable.
0:04 Greetings, Math Crusader!
0:07 Captain Calc needs your analytical powers to solve secret code equations and save Math City.
0:14 Understanding Linear Equations in One Variable.
0:18 An algebraic equation is a statement showing two expressions are equal.
0:23 A linear equation in one variable contains only one unknown letter, and its highest power is 1.
0:30 Try this one. Solve for x: 3x - 7 = 14
0:37 Add 7 to both sides: 3x = 14 + 7
0:42 Simplify: 3x = 21
0:45 Divide both sides by 3: x = 7
0:49 So the answer is x = 7.
0:53 Variables on Both Sides.
0:55 Sometimes the unknown variable appears on both the left and right sides of the equation.
1:01 Collect all terms containing the variable on one side using addition or subtraction.
1:08 Try this one. Solve for x: 5x + 4 = 3x + 12
1:15 Subtract 3x from both sides: 2x + 4 = 12
1:20 Subtract 4 from both sides: 2x = 8
1:24 Divide both sides by 2: x = 4
1:28 So the answer is x = 4.
1:31 Equations with Brackets and Fractions.
1:35 When an equation has brackets, use the distributive property to expand them first.
1:40 If fractions are present, multiply the entire equation by the common denominator to clear them.
1:47 Try this one. Solve for x: 3(x - 2) = 15
1:53 Expand brackets: 3x - 6 = 15
1:58 Add 6 to both sides: 3x = 21
2:02 Divide by 3: x = 7
2:05 So the answer is x = 7.
2:08 Solving Real-Life Word Problems.
2:11 Read the problem carefully and choose a variable letter for the unknown quantity.
2:17 Translate the words into an algebraic equation using mathematical operations.
2:23 Try this one. The sum of two consecutive numbers is 31. Find the smaller number.
2:30 Let the smaller number be x. The next number is x + 1.
2:35 Write equation: x + (x + 1) = 31
2:40 Combine terms: 2x + 1 = 31
2:44 Subtract 1: 2x = 30, so x = 15
2:49 So the answer is 15.
2:52 Your turn. Solve: 3m = 21 Pause the video, and try it.
2:60 The answer is 7.
3:02 Well done! Now try the practice and the quiz in this lesson on LearnFun.
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