2x^2-5x-6=0 eching

$$2 x ^ { 2 } - 5 x - 6 = 0$$

x uchun yechish

$$x = \frac{\sqrt{73} + 5}{4} \approx 3,386000936$$

$$x=\frac{5-\sqrt{73}}{4}\approx -0,886000936$$

Kvadrat tenglamalaridan foydalanish qoidalari

ax^{2}+bx+c=0 shaklidagi barcha tenglamalarni kvadrat formulasi bilan yechish mumkin: \frac{-b±\sqrt{b^{2}-4ac}}{2a}. Kvadrat formula ikki yechmni taqdim qiladi, biri ± qo'shish bo'lganda, va ikkinchisi ayiruv bo'lganda.

$$2x^{2}-5x-6=0$$

Ushbu tenglama standart shaklidadir: ax^{2}+bx+c=0. Kvadrat tenglama formulasida, \frac{-b±\sqrt{b^{2}-4ac}}{2a} 2 ni a, -5 ni b va -6 ni c bilan almashtiring.

$$x=\frac{-\left(-5\right)±\sqrt{\left(-5\right)^{2}-4\times 2\left(-6\right)}}{2\times 2}$$

-5 kvadratini chiqarish.

$$x=\frac{-\left(-5\right)±\sqrt{25-4\times 2\left(-6\right)}}{2\times 2}$$

-4 ni 2 marotabaga ko'paytirish.

$$x=\frac{-\left(-5\right)±\sqrt{25-8\left(-6\right)}}{2\times 2}$$

-8 ni -6 marotabaga ko'paytirish.

$$x=\frac{-\left(-5\right)±\sqrt{25+48}}{2\times 2}$$

25 ni 48 ga qo'shish.

$$x=\frac{-\left(-5\right)±\sqrt{73}}{2\times 2}$$

-5 ning teskarisi 5 ga teng.

$$x=\frac{5±\sqrt{73}}{2\times 2}$$

2 ni 2 marotabaga ko'paytirish.

$$x=\frac{5±\sqrt{73}}{4}$$

x=\frac{5±\sqrt{73}}{4} tenglamasini yeching, bunda ± musbat. 5 ni \sqrt{73} ga qo'shish.

$$x=\frac{\sqrt{73}+5}{4}$$

x=\frac{5±\sqrt{73}}{4} tenglamasini yeching, bunda ± manfiy. 5 dan \sqrt{73} ni ayirish.

$$x=\frac{5-\sqrt{73}}{4}$$

Tenglama yechildi.

$$x=\frac{\sqrt{73}+5}{4} x=\frac{5-\sqrt{73}}{4}$$

Kvadratni yakunlash bo'yicha qadamlar

Bu kabi kvadrat tenglamalarni kvadratni yakunlab yechish mumkin. Kvadratni yechish uchun tenglama avval ushbu shaklda bo'lishi shart: x^{2}+bx=c.

$$2x^{2}-5x-6=0$$

6 ni tenglamaning ikkala tarafiga qo'shish.

$$2x^{2}-5x-6-\left(-6\right)=-\left(-6\right)$$

O‘zidan -6 ayirilsa 0 qoladi.

$$2x^{2}-5x=-\left(-6\right)$$

0 dan -6 ni ayirish.

$$2x^{2}-5x=6$$

Ikki tarafini 2 ga bo‘ling.

$$\frac{2x^{2}-5x}{2}=\frac{6}{2}$$

2 ga bo'lish 2 ga ko'paytirishni bekor qiladi.

$$x^{2}-\frac{5}{2}x=\frac{6}{2}$$

6 ni 2 ga bo'lish.

$$x^{2}-\frac{5}{2}x=3$$

-\frac{5}{2} ni bo‘lish, x shartining koeffitsienti, 2 ga -\frac{5}{4} olish uchun. Keyin, -\frac{5}{4} ning kvadratini tenglamaning ikkala tarafiga qo‘shing. Ushbu qadam tenglamaning chap qismini mukammal kvadrat sifatida hosil qiladi.

$$x^{2}-\frac{5}{2}x+\left(-\frac{5}{4}\right)^{2}=3+\left(-\frac{5}{4}\right)^{2}$$

Kasrning ham suratini, ham maxrajini kvadratga ko'paytirib -\frac{5}{4} kvadratini chiqarish.

$$x^{2}-\frac{5}{2}x+\frac{25}{16}=3+\frac{25}{16}$$

3 ni \frac{25}{16} ga qo'shish.

$$x^{2}-\frac{5}{2}x+\frac{25}{16}=\frac{73}{16}$$

x^{2}-\frac{5}{2}x+\frac{25}{16} omili. Odatda, x^{2}+bx+c mukammal kvadrat bo'lsa, u doimo \left(x+\frac{b}{2}\right)^{2} omil sifatida bo'lishi mumkin.

$$\left(x-\frac{5}{4}\right)^{2}=\frac{73}{16}$$

Tenglamaning ikkala tarafining kvadrat ildizini chiqarish.

$$\sqrt{\left(x-\frac{5}{4}\right)^{2}}=\sqrt{\frac{73}{16}}$$

Qisqartirish.

$$x-\frac{5}{4}=\frac{\sqrt{73}}{4} x-\frac{5}{4}=-\frac{\sqrt{73}}{4}$$

\frac{5}{4} ni tenglamaning ikkala tarafiga qo'shish.

$$x=\frac{\sqrt{73}+5}{4} x=\frac{5-\sqrt{73}}{4}$$