x^2+5x+1=0 eching

$${ x }^{ 2 } +5x+1=0$$

x uchun yechish

$$x=\frac{\sqrt{21}-5}{2}\approx -0,208712153$$

$$x=\frac{-\sqrt{21}-5}{2}\approx -4,791287847$$

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.

$$x^{2}+5x+1=0$$

Ushbu tenglama standart shaklidadir: ax^{2}+bx+c=0. Kvadrat tenglama formulasida, \frac{-b±\sqrt{b^{2}-4ac}}{2a} 1 ni a, 5 ni b va 1 ni c bilan almashtiring.

$$x=\frac{-5±\sqrt{5^{2}-4}}{2}$$

5 kvadratini chiqarish.

$$x=\frac{-5±\sqrt{25-4}}{2}$$

25 ni -4 ga qo'shish.

$$x=\frac{-5±\sqrt{21}}{2}$$

x=\frac{-5±\sqrt{21}}{2} tenglamasini yeching, bunda ± musbat. -5 ni \sqrt{21} ga qo'shish.

$$x=\frac{\sqrt{21}-5}{2}$$

x=\frac{-5±\sqrt{21}}{2} tenglamasini yeching, bunda ± manfiy. -5 dan \sqrt{21} ni ayirish.

$$x=\frac{-\sqrt{21}-5}{2}$$

Tenglama yechildi.

$$x=\frac{\sqrt{21}-5}{2} x=\frac{-\sqrt{21}-5}{2}$$

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.

$$x^{2}+5x+1=0$$

Tenglamaning ikkala tarafidan 1 ni ayirish.

$$x^{2}+5x+1-1=-1$$

O‘zidan 1 ayirilsa 0 qoladi.

$$x^{2}+5x=-1$$

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

$$x^{2}+5x+\left(\frac{5}{2}\right)^{2}=-1+\left(\frac{5}{2}\right)^{2}$$

Kasrning ham suratini, ham maxrajini kvadratga ko'paytirib \frac{5}{2} kvadratini chiqarish.

$$x^{2}+5x+\frac{25}{4}=-1+\frac{25}{4}$$

-1 ni \frac{25}{4} ga qo'shish.

$$x^{2}+5x+\frac{25}{4}=\frac{21}{4}$$

x^{2}+5x+\frac{25}{4} omili. Odatda, x^{2}+bx+c mukammal kvadrat bo'lsa, u doimo \left(x+\frac{b}{2}\right)^{2} omil sifatida bo'lishi mumkin.

$$\left(x+\frac{5}{2}\right)^{2}=\frac{21}{4}$$

Tenglamaning ikkala tarafining kvadrat ildizini chiqarish.

$$\sqrt{\left(x+\frac{5}{2}\right)^{2}}=\sqrt{\frac{21}{4}}$$

Qisqartirish.

$$x+\frac{5}{2}=\frac{\sqrt{21}}{2} x+\frac{5}{2}=-\frac{\sqrt{21}}{2}$$

Tenglamaning ikkala tarafidan \frac{5}{2} ni ayirish.

$$x=\frac{\sqrt{21}-5}{2} x=\frac{-\sqrt{21}-5}{2}$$