28-21x^2=0 eching

$$28 - 21 x ^ { 2 } = 0$$

x uchun yechish

$$x = \frac{2 \sqrt{3}}{3} \approx 1,154700538$$

$$x = -\frac{2 \sqrt{3}}{3} \approx -1,154700538$$

Kvadrat ildizini topish bo'yicha qadamlar

Ikkala tarafdan 28 ni ayirish. Har qanday sonni noldan ayirsangiz, o‘zining manfiyi chiqadi.

$$-21x^{2}=-28$$

Ikki tarafini -21 ga bo‘ling.

$$x^{2}=\frac{-28}{-21}$$

\frac{-28}{-21} ulushini -7 ni chiqarib, bekor qilish hisobiga eng past shartlarga kamaytiring.

$$x^{2}=\frac{4}{3}$$

Tenglamaning ikkala tarafining kvadrat ildizini chiqarish.

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

Kvadrat tenglamalaridan foydalanish qoidalari

Bu kabi kvadrat tenglamalarni x^{2} sharti bilan, biroq x shartisiz hamon kvadrat tenglamasidan foydalanib yechish mumkin, \frac{-b±\sqrt{b^{2}-4ac}}{2a}, ular standart formulaga solingandan so'ng: ax^{2}+bx+c=0.

$$-21x^{2}+28=0$$

Ushbu tenglama standart shaklidadir: ax^{2}+bx+c=0. Kvadrat tenglama formulasida, \frac{-b±\sqrt{b^{2}-4ac}}{2a} -21 ni a, 0 ni b va 28 ni c bilan almashtiring.

$$x=\frac{0±\sqrt{0^{2}-4\left(-21\right)\times 28}}{2\left(-21\right)}$$

0 kvadratini chiqarish.

$$x=\frac{0±\sqrt{-4\left(-21\right)\times 28}}{2\left(-21\right)}$$

-4 ni -21 marotabaga ko'paytirish.

$$x=\frac{0±\sqrt{84\times 28}}{2\left(-21\right)}$$

84 ni 28 marotabaga ko'paytirish.

$$x=\frac{0±\sqrt{2352}}{2\left(-21\right)}$$

2352 ning kvadrat ildizini chiqarish.

$$x=\frac{0±28\sqrt{3}}{2\left(-21\right)}$$

2 ni -21 marotabaga ko'paytirish.

$$x=\frac{0±28\sqrt{3}}{-42}$$

x=\frac{0±28\sqrt{3}}{-42} tenglamasini yeching, bunda ± musbat.

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

x=\frac{0±28\sqrt{3}}{-42} tenglamasini yeching, bunda ± manfiy.

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

Tenglama yechildi.

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