x uchun yechish (complex solution)
x=\frac{-5+3\sqrt{59}i}{2}\approx -2,5+11,521718622i
x=\frac{-3\sqrt{59}i-5}{2}\approx -2,5-11,521718622i
Grafik
Baham ko'rish
Klipbordga nusxa olish
x^{2}+5x+139=0
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=\frac{-5±\sqrt{5^{2}-4\times 139}}{2}
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 139 ni c bilan almashtiring.
x=\frac{-5±\sqrt{25-4\times 139}}{2}
5 kvadratini chiqarish.
x=\frac{-5±\sqrt{25-556}}{2}
-4 ni 139 marotabaga ko'paytirish.
x=\frac{-5±\sqrt{-531}}{2}
25 ni -556 ga qo'shish.
x=\frac{-5±3\sqrt{59}i}{2}
-531 ning kvadrat ildizini chiqarish.
x=\frac{-5+3\sqrt{59}i}{2}
x=\frac{-5±3\sqrt{59}i}{2} tenglamasini yeching, bunda ± musbat. -5 ni 3i\sqrt{59} ga qo'shish.
x=\frac{-3\sqrt{59}i-5}{2}
x=\frac{-5±3\sqrt{59}i}{2} tenglamasini yeching, bunda ± manfiy. -5 dan 3i\sqrt{59} ni ayirish.
x=\frac{-5+3\sqrt{59}i}{2} x=\frac{-3\sqrt{59}i-5}{2}
Tenglama yechildi.
x^{2}+5x+139=0
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+139-139=-139
Tenglamaning ikkala tarafidan 139 ni ayirish.
x^{2}+5x=-139
O‘zidan 139 ayirilsa 0 qoladi.
x^{2}+5x+\left(\frac{5}{2}\right)^{2}=-139+\left(\frac{5}{2}\right)^{2}
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+\frac{25}{4}=-139+\frac{25}{4}
Kasrning ham suratini, ham maxrajini kvadratga ko'paytirib \frac{5}{2} kvadratini chiqarish.
x^{2}+5x+\frac{25}{4}=-\frac{531}{4}
-139 ni \frac{25}{4} ga qo'shish.
\left(x+\frac{5}{2}\right)^{2}=-\frac{531}{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.
\sqrt{\left(x+\frac{5}{2}\right)^{2}}=\sqrt{-\frac{531}{4}}
Tenglamaning ikkala tarafining kvadrat ildizini chiqarish.
x+\frac{5}{2}=\frac{3\sqrt{59}i}{2} x+\frac{5}{2}=-\frac{3\sqrt{59}i}{2}
Qisqartirish.
x=\frac{-5+3\sqrt{59}i}{2} x=\frac{-3\sqrt{59}i-5}{2}
Tenglamaning ikkala tarafidan \frac{5}{2} ni ayirish.
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