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บทเรียนพีชคณิต: วิธีแก้โจทย์พีชคณิต

โจทย์พีชคณิตทุกข้อมาจากไม่กี่ขั้น: ทำให้ง่าย ทำแบบเดียวกันทั้งสองข้าง และตรวจสอบ บทเรียนเหล่านี้สอนแต่ละขั้นด้วยตัวอย่างที่แก้แล้ว ซึ่งคำตอบผ่านการตรวจโดยเครื่องมือคณิตศาสตร์ของ Sumzo

18 บทความ

• อ่าน 5 นาที

  Equations: what they are and how to solve them

  What an equation is, what its solution means, and how to solve equations step by step — from one-step equations to fractions and two variables.

• อ่าน 1 นาที

  Solving linear equations

  Use inverse operations to get the unknown on its own, keep the equation balanced, and always check your answer.

• อ่าน 2 นาที

  Quadratic equations: how to solve them

  Factorising, completing the square, the quadratic formula and the discriminant — and how to tell which method to use.

• อ่าน 1 นาที

  Slope and the equation of a line

  What slope measures, how to find it from two points, and how to write a line as y = mx + b.

• อ่าน 4 นาที

  How to simplify radicals (simplest radical form)

  How to simplify radicals by taking out perfect-square factors, what simplest radical form means, and how to simplify radical expressions — with checked examples.

• อ่าน 2 นาที

  Rational equations: how to solve them

  What a rational equation is, how to solve rational equations by multiplying by the lowest common denominator, and why every answer must be checked.

• อ่าน 3 นาที

  Factoring polynomials: a step-by-step guide

  The steps for factoring polynomials — common factor first, then two, three or four terms — with worked examples, each checked by multiplying back out.

• อ่าน 3 นาที

  Solving inequalities: how to solve and graph them

  Solving inequalities like equations — with one extra rule — and showing the answer on a number line, in interval notation and as a shaded region.

• อ่าน 2 นาที

  What is a solution in math? Examples with one, none or many

  A solution is a value that makes an equation true. How to check one, and examples with one solution, no solution, all real numbers and two solutions.

• อ่าน 2 นาที

  How to solve a word problem: 5 steps that work

  A five-step method for solving word problems, the key words that turn into maths, and worked examples — ages, consecutive numbers, discounts and tickets.

• อ่าน 2 นาที

  How to graph an equation: lines, parabolas and more

  Three ways to graph an equation — a table of values, slope and intercept, and key points of a parabola — with worked examples and how to match a graph to its equation.

• อ่าน 3 นาที

  Functions: how to graph a function, domain, range and f(g(x))

  Function notation, how to graph a function from its formula, how to find its domain and range, and how composite functions such as f(g(x)) work.

• อ่าน 2 นาที

  Polynomials: how to simplify, expand and solve them

  What a polynomial is, how to simplify and expand polynomials, and how to solve polynomial equations by factoring — with checked examples.

• อ่าน 2 นาที

  Rational expressions: simplify, multiply, divide, add and subtract

  What rational expressions are, their excluded values, and how to simplify, multiply, divide, add and subtract them — then solve rational equations.

• อ่าน 2 นาที

  How to solve literal equations (rearranging formulas)

  A literal equation has several letters. Solving it means isolating one of them — the same moves as an ordinary equation, with letters instead of numbers.

• อ่าน 1 นาที

  How to simplify expressions and complex fractions

  How to simplify the following kinds of expression: like terms, brackets, exponents and complex fractions (a fraction inside a fraction), each with checked examples.

• อ่าน 1 นาที

  Find x: how to solve for x in equations, angles and triangles

  The questions that say “find x” — equations, angles on a line, triangle angles, Pythagoras and similar shapes — and the one idea behind all of them.

• อ่าน 2 นาที

  Systems of equations and graphing systems of linear inequalities

  How to find the solution to a system of equations three ways, then how to graph a system of inequalities: boundary lines, shading and the overlap.