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Linear equations

Isolate the unknown by doing the same thing to both sides.

A linear equation has the unknown to the first power only. Solving it is a sequence of legal moves (add, subtract, multiply or divide both sides by the same thing) chosen to leave the unknown alone. The graph shows the line y = 2x + 3 − 7; the solution is where it crosses the axis.

Vinna dæmi · 2x + 3 = 7

Algebra · Linear-Equations

Solve 2x + 3 = 7

2 x + 3 = 7

Skref fyrir skref

  1. 2 x + 3 = 7

    Start from the equation as given.

  2. 2 x - 4 = 0

    Bring everything to one side and collect like terms so the right-hand side is 0.

  3. 2 x = 4

    Move the constant term to the other side: subtract -4 from both sides.

  4. x = \frac{4}{2}

    Divide both sides by 2, the coefficient of x.

  5. x = 2

    Simplify the fraction.

Sýna svarið
x = 2

Núna ūú Veldu vandamál, eða sláðu inn eða teikna eigin. Hvert skref, mynd, svarið falið þar til þú spyrð.

Haltu eigin vinnu þinni

Ókeypis reikningur bætir við athugasemdum við hverja kennslustund, skrá yfir það sem þú hefur lokið, leyst vandamál á einum stað og kennari sem þú getur spurt um þessa síðu.Stærðfræðin sjálf er opin öllum, skráður inn eða ekki.

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Tákn notuð hér

Pikkaðu á hvaða tákn sem er fyrir fulla skilgreiningu, mynd og hvað hvert bréf í því merkir.

Hvernig á að nota: Linear equations

  1. Start from the equation as given.
  2. Bring everything to one side and collect like terms so the right-hand side is 0.
  3. Move the constant term to the other side: subtract -4 from both sides.
  4. Divide both sides by 2, the coefficient of x.
  5. Simplify the fraction.

Spurningar sem fólk spyr

What does it mean to solve an equation?

To find every value of the unknown that makes both sides equal. Each step is an operation applied to both sides that keeps the solution set the same, until the unknown stands alone.

Why do I sometimes get two answers?

A quadratic can cross the axis twice, so it can have two solutions. A degree-n polynomial has up to n. The graph shows where each one comes from.

How do I know whether to factor or use the quadratic formula?

Try factoring for a few seconds: look for two numbers that multiply to a·c and add to b. If nothing obvious appears, the discriminant b² − 4ac tells you how many real roots there are, and the formula finds them without guessing.

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