x^2+3x-5=12 eching

$$x ^ { 2 } + 3 x - 5 = 12$$

x uchun yechish

$$x = \frac{\sqrt{77} - 3}{2} \approx 2,887482194$$

$$x=\frac{-\sqrt{77}-3}{2}\approx -5,887482194$$

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.

$$x^{2}+3x-5=12$$

Tenglamaning ikkala tarafidan 12 ni ayirish.

$$x^{2}+3x-5-12=12-12$$

O‘zidan 12 ayirilsa 0 qoladi.

$$x^{2}+3x-5-12=0$$

-5 dan 12 ni ayirish.

$$x^{2}+3x-17=0$$

Ushbu tenglama standart shaklidadir: ax^{2}+bx+c=0. Kvadrat tenglama formulasida, \frac{-b±\sqrt{b^{2}-4ac}}{2a} 1 ni a, 3 ni b va -17 ni c bilan almashtiring.

$$x=\frac{-3±\sqrt{3^{2}-4\left(-17\right)}}{2}$$

3 kvadratini chiqarish.

$$x=\frac{-3±\sqrt{9-4\left(-17\right)}}{2}$$

-4 ni -17 marotabaga ko'paytirish.

$$x=\frac{-3±\sqrt{9+68}}{2}$$

9 ni 68 ga qo'shish.

$$x=\frac{-3±\sqrt{77}}{2}$$

x=\frac{-3±\sqrt{77}}{2} tenglamasini yeching, bunda ± musbat. -3 ni \sqrt{77} ga qo'shish.

$$x=\frac{\sqrt{77}-3}{2}$$

x=\frac{-3±\sqrt{77}}{2} tenglamasini yeching, bunda ± manfiy. -3 dan \sqrt{77} ni ayirish.

$$x=\frac{-\sqrt{77}-3}{2}$$

Tenglama yechildi.

$$x=\frac{\sqrt{77}-3}{2} x=\frac{-\sqrt{77}-3}{2}$$

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.

$$x^{2}+3x-5=12$$

5 ni tenglamaning ikkala tarafiga qo'shish.

$$x^{2}+3x-5-\left(-5\right)=12-\left(-5\right)$$

O‘zidan -5 ayirilsa 0 qoladi.

$$x^{2}+3x=12-\left(-5\right)$$

12 dan -5 ni ayirish.

$$x^{2}+3x=17$$

3 ni bo‘lish, x shartining koeffitsienti, 2 ga \frac{3}{2} olish uchun. Keyin, \frac{3}{2} ning kvadratini tenglamaning ikkala tarafiga qo‘shing. Ushbu qadam tenglamaning chap qismini mukammal kvadrat sifatida hosil qiladi.

$$x^{2}+3x+\left(\frac{3}{2}\right)^{2}=17+\left(\frac{3}{2}\right)^{2}$$

Kasrning ham suratini, ham maxrajini kvadratga ko'paytirib \frac{3}{2} kvadratini chiqarish.

$$x^{2}+3x+\frac{9}{4}=17+\frac{9}{4}$$

17 ni \frac{9}{4} ga qo'shish.

$$x^{2}+3x+\frac{9}{4}=\frac{77}{4}$$

x^{2}+3x+\frac{9}{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.

$$\left(x+\frac{3}{2}\right)^{2}=\frac{77}{4}$$

Tenglamaning ikkala tarafining kvadrat ildizini chiqarish.

$$\sqrt{\left(x+\frac{3}{2}\right)^{2}}=\sqrt{\frac{77}{4}}$$

Qisqartirish.

$$x+\frac{3}{2}=\frac{\sqrt{77}}{2} x+\frac{3}{2}=-\frac{\sqrt{77}}{2}$$

Tenglamaning ikkala tarafidan \frac{3}{2} ni ayirish.

$$x=\frac{\sqrt{77}-3}{2} x=\frac{-\sqrt{77}-3}{2}$$