t uchun yechish
t = \frac{2 \sqrt{43} + 16}{7} \approx 4,15926815
t=\frac{16-2\sqrt{43}}{7}\approx 0,412160422
Baham ko'rish
Klipbordga nusxa olish
7t^{2}-32t+12=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.
t=\frac{-\left(-32\right)±\sqrt{\left(-32\right)^{2}-4\times 7\times 12}}{2\times 7}
Ushbu tenglama standart shaklidadir: ax^{2}+bx+c=0. Kvadrat tenglama formulasida, \frac{-b±\sqrt{b^{2}-4ac}}{2a} 7 ni a, -32 ni b va 12 ni c bilan almashtiring.
t=\frac{-\left(-32\right)±\sqrt{1024-4\times 7\times 12}}{2\times 7}
-32 kvadratini chiqarish.
t=\frac{-\left(-32\right)±\sqrt{1024-28\times 12}}{2\times 7}
-4 ni 7 marotabaga ko'paytirish.
t=\frac{-\left(-32\right)±\sqrt{1024-336}}{2\times 7}
-28 ni 12 marotabaga ko'paytirish.
t=\frac{-\left(-32\right)±\sqrt{688}}{2\times 7}
1024 ni -336 ga qo'shish.
t=\frac{-\left(-32\right)±4\sqrt{43}}{2\times 7}
688 ning kvadrat ildizini chiqarish.
t=\frac{32±4\sqrt{43}}{2\times 7}
-32 ning teskarisi 32 ga teng.
t=\frac{32±4\sqrt{43}}{14}
2 ni 7 marotabaga ko'paytirish.
t=\frac{4\sqrt{43}+32}{14}
t=\frac{32±4\sqrt{43}}{14} tenglamasini yeching, bunda ± musbat. 32 ni 4\sqrt{43} ga qo'shish.
t=\frac{2\sqrt{43}+16}{7}
32+4\sqrt{43} ni 14 ga bo'lish.
t=\frac{32-4\sqrt{43}}{14}
t=\frac{32±4\sqrt{43}}{14} tenglamasini yeching, bunda ± manfiy. 32 dan 4\sqrt{43} ni ayirish.
t=\frac{16-2\sqrt{43}}{7}
32-4\sqrt{43} ni 14 ga bo'lish.
t=\frac{2\sqrt{43}+16}{7} t=\frac{16-2\sqrt{43}}{7}
Tenglama yechildi.
7t^{2}-32t+12=0
Bu kabi kvadrat tenglamalarni kvadratni yakunlab yechish mumkin. Kvadratni yechish uchun tenglama avval ushbu shaklda bo'lishi shart: x^{2}+bx=c.
7t^{2}-32t+12-12=-12
Tenglamaning ikkala tarafidan 12 ni ayirish.
7t^{2}-32t=-12
O‘zidan 12 ayirilsa 0 qoladi.
\frac{7t^{2}-32t}{7}=-\frac{12}{7}
Ikki tarafini 7 ga bo‘ling.
t^{2}-\frac{32}{7}t=-\frac{12}{7}
7 ga bo'lish 7 ga ko'paytirishni bekor qiladi.
t^{2}-\frac{32}{7}t+\left(-\frac{16}{7}\right)^{2}=-\frac{12}{7}+\left(-\frac{16}{7}\right)^{2}
-\frac{32}{7} ni bo‘lish, x shartining koeffitsienti, 2 ga -\frac{16}{7} olish uchun. Keyin, -\frac{16}{7} ning kvadratini tenglamaning ikkala tarafiga qo‘shing. Ushbu qadam tenglamaning chap qismini mukammal kvadrat sifatida hosil qiladi.
t^{2}-\frac{32}{7}t+\frac{256}{49}=-\frac{12}{7}+\frac{256}{49}
Kasrning ham suratini, ham maxrajini kvadratga ko'paytirib -\frac{16}{7} kvadratini chiqarish.
t^{2}-\frac{32}{7}t+\frac{256}{49}=\frac{172}{49}
Umumiy maxrajni topib va hisoblovchini qo'shish orqali -\frac{12}{7} ni \frac{256}{49} ga qo'shing. So'ngra agar imkoni bo'lsa kasrni eng kam shartga qisqartiring.
\left(t-\frac{16}{7}\right)^{2}=\frac{172}{49}
t^{2}-\frac{32}{7}t+\frac{256}{49} 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(t-\frac{16}{7}\right)^{2}}=\sqrt{\frac{172}{49}}
Tenglamaning ikkala tarafining kvadrat ildizini chiqarish.
t-\frac{16}{7}=\frac{2\sqrt{43}}{7} t-\frac{16}{7}=-\frac{2\sqrt{43}}{7}
Qisqartirish.
t=\frac{2\sqrt{43}+16}{7} t=\frac{16-2\sqrt{43}}{7}
\frac{16}{7} ni tenglamaning ikkala tarafiga qo'shish.
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