x uchun yechish (complex solution)
x=\frac{-15+10\sqrt{10}i}{49}\approx -0,306122449+0,645362788i
x=\frac{-10\sqrt{10}i-15}{49}\approx -0,306122449-0,645362788i
Grafik
Baham ko'rish
Klipbordga nusxa olish
49x^{2}+30x+25=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{-30±\sqrt{30^{2}-4\times 49\times 25}}{2\times 49}
Ushbu tenglama standart shaklidadir: ax^{2}+bx+c=0. Kvadrat tenglama formulasida, \frac{-b±\sqrt{b^{2}-4ac}}{2a} 49 ni a, 30 ni b va 25 ni c bilan almashtiring.
x=\frac{-30±\sqrt{900-4\times 49\times 25}}{2\times 49}
30 kvadratini chiqarish.
x=\frac{-30±\sqrt{900-196\times 25}}{2\times 49}
-4 ni 49 marotabaga ko'paytirish.
x=\frac{-30±\sqrt{900-4900}}{2\times 49}
-196 ni 25 marotabaga ko'paytirish.
x=\frac{-30±\sqrt{-4000}}{2\times 49}
900 ni -4900 ga qo'shish.
x=\frac{-30±20\sqrt{10}i}{2\times 49}
-4000 ning kvadrat ildizini chiqarish.
x=\frac{-30±20\sqrt{10}i}{98}
2 ni 49 marotabaga ko'paytirish.
x=\frac{-30+20\sqrt{10}i}{98}
x=\frac{-30±20\sqrt{10}i}{98} tenglamasini yeching, bunda ± musbat. -30 ni 20i\sqrt{10} ga qo'shish.
x=\frac{-15+10\sqrt{10}i}{49}
-30+20i\sqrt{10} ni 98 ga bo'lish.
x=\frac{-20\sqrt{10}i-30}{98}
x=\frac{-30±20\sqrt{10}i}{98} tenglamasini yeching, bunda ± manfiy. -30 dan 20i\sqrt{10} ni ayirish.
x=\frac{-10\sqrt{10}i-15}{49}
-30-20i\sqrt{10} ni 98 ga bo'lish.
x=\frac{-15+10\sqrt{10}i}{49} x=\frac{-10\sqrt{10}i-15}{49}
Tenglama yechildi.
49x^{2}+30x+25=0
Bu kabi kvadrat tenglamalarni kvadratni yakunlab yechish mumkin. Kvadratni yechish uchun tenglama avval ushbu shaklda bo'lishi shart: x^{2}+bx=c.
49x^{2}+30x+25-25=-25
Tenglamaning ikkala tarafidan 25 ni ayirish.
49x^{2}+30x=-25
O‘zidan 25 ayirilsa 0 qoladi.
\frac{49x^{2}+30x}{49}=-\frac{25}{49}
Ikki tarafini 49 ga bo‘ling.
x^{2}+\frac{30}{49}x=-\frac{25}{49}
49 ga bo'lish 49 ga ko'paytirishni bekor qiladi.
x^{2}+\frac{30}{49}x+\left(\frac{15}{49}\right)^{2}=-\frac{25}{49}+\left(\frac{15}{49}\right)^{2}
\frac{30}{49} ni bo‘lish, x shartining koeffitsienti, 2 ga \frac{15}{49} olish uchun. Keyin, \frac{15}{49} ning kvadratini tenglamaning ikkala tarafiga qo‘shing. Ushbu qadam tenglamaning chap qismini mukammal kvadrat sifatida hosil qiladi.
x^{2}+\frac{30}{49}x+\frac{225}{2401}=-\frac{25}{49}+\frac{225}{2401}
Kasrning ham suratini, ham maxrajini kvadratga ko'paytirib \frac{15}{49} kvadratini chiqarish.
x^{2}+\frac{30}{49}x+\frac{225}{2401}=-\frac{1000}{2401}
Umumiy maxrajni topib va hisoblovchini qo'shish orqali -\frac{25}{49} ni \frac{225}{2401} ga qo'shing. So'ngra agar imkoni bo'lsa kasrni eng kam shartga qisqartiring.
\left(x+\frac{15}{49}\right)^{2}=-\frac{1000}{2401}
x^{2}+\frac{30}{49}x+\frac{225}{2401} 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{15}{49}\right)^{2}}=\sqrt{-\frac{1000}{2401}}
Tenglamaning ikkala tarafining kvadrat ildizini chiqarish.
x+\frac{15}{49}=\frac{10\sqrt{10}i}{49} x+\frac{15}{49}=-\frac{10\sqrt{10}i}{49}
Qisqartirish.
x=\frac{-15+10\sqrt{10}i}{49} x=\frac{-10\sqrt{10}i-15}{49}
Tenglamaning ikkala tarafidan \frac{15}{49} ni ayirish.
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