x uchun yechish
x=-30
x=60
Grafik
Baham ko'rish
Klipbordga nusxa olish
x^{2}-30x-1800=0
Ikki tarafini 2 ga bo‘ling.
a+b=-30 ab=1\left(-1800\right)=-1800
Tenglamani yechish uchun guruhlash orqali chap qoʻl tomonni faktorlang. Avvalo, chap qoʻl tomon x^{2}+ax+bx-1800 sifatida qayta yozilishi kerak. a va b ni topish uchun yechiladigan tizimni sozlang.
1,-1800 2,-900 3,-600 4,-450 5,-360 6,-300 8,-225 9,-200 10,-180 12,-150 15,-120 18,-100 20,-90 24,-75 25,-72 30,-60 36,-50 40,-45
ab manfiy boʻlganda, a va b da qarama-qarshi belgilar bor. a+b manfiy boʻlganda, manfiy sonda musbatga nisbatdan kattaroq mutlaq qiymat bor. -1800-mahsulotni beruvchi bunday butun juftliklarni roʻyxat qiling.
1-1800=-1799 2-900=-898 3-600=-597 4-450=-446 5-360=-355 6-300=-294 8-225=-217 9-200=-191 10-180=-170 12-150=-138 15-120=-105 18-100=-82 20-90=-70 24-75=-51 25-72=-47 30-60=-30 36-50=-14 40-45=-5
Har bir juftlik yigʻindisini hisoblang.
a=-60 b=30
Yechim – -30 yigʻindisini beruvchi juftlik.
\left(x^{2}-60x\right)+\left(30x-1800\right)
x^{2}-30x-1800 ni \left(x^{2}-60x\right)+\left(30x-1800\right) sifatida qaytadan yozish.
x\left(x-60\right)+30\left(x-60\right)
Birinchi guruhda x ni va ikkinchi guruhda 30 ni faktordan chiqaring.
\left(x-60\right)\left(x+30\right)
Distributiv funktsiyasidan foydalangan holda x-60 umumiy terminini chiqaring.
x=60 x=-30
Tenglamani yechish uchun x-60=0 va x+30=0 ni yeching.
2x^{2}-60x-3600=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{-\left(-60\right)±\sqrt{\left(-60\right)^{2}-4\times 2\left(-3600\right)}}{2\times 2}
Ushbu tenglama standart shaklidadir: ax^{2}+bx+c=0. Kvadrat tenglama formulasida, \frac{-b±\sqrt{b^{2}-4ac}}{2a} 2 ni a, -60 ni b va -3600 ni c bilan almashtiring.
x=\frac{-\left(-60\right)±\sqrt{3600-4\times 2\left(-3600\right)}}{2\times 2}
-60 kvadratini chiqarish.
x=\frac{-\left(-60\right)±\sqrt{3600-8\left(-3600\right)}}{2\times 2}
-4 ni 2 marotabaga ko'paytirish.
x=\frac{-\left(-60\right)±\sqrt{3600+28800}}{2\times 2}
-8 ni -3600 marotabaga ko'paytirish.
x=\frac{-\left(-60\right)±\sqrt{32400}}{2\times 2}
3600 ni 28800 ga qo'shish.
x=\frac{-\left(-60\right)±180}{2\times 2}
32400 ning kvadrat ildizini chiqarish.
x=\frac{60±180}{2\times 2}
-60 ning teskarisi 60 ga teng.
x=\frac{60±180}{4}
2 ni 2 marotabaga ko'paytirish.
x=\frac{240}{4}
x=\frac{60±180}{4} tenglamasini yeching, bunda ± musbat. 60 ni 180 ga qo'shish.
x=60
240 ni 4 ga bo'lish.
x=-\frac{120}{4}
x=\frac{60±180}{4} tenglamasini yeching, bunda ± manfiy. 60 dan 180 ni ayirish.
x=-30
-120 ni 4 ga bo'lish.
x=60 x=-30
Tenglama yechildi.
2x^{2}-60x-3600=0
Bu kabi kvadrat tenglamalarni kvadratni yakunlab yechish mumkin. Kvadratni yechish uchun tenglama avval ushbu shaklda bo'lishi shart: x^{2}+bx=c.
2x^{2}-60x-3600-\left(-3600\right)=-\left(-3600\right)
3600 ni tenglamaning ikkala tarafiga qo'shish.
2x^{2}-60x=-\left(-3600\right)
O‘zidan -3600 ayirilsa 0 qoladi.
2x^{2}-60x=3600
0 dan -3600 ni ayirish.
\frac{2x^{2}-60x}{2}=\frac{3600}{2}
Ikki tarafini 2 ga bo‘ling.
x^{2}+\left(-\frac{60}{2}\right)x=\frac{3600}{2}
2 ga bo'lish 2 ga ko'paytirishni bekor qiladi.
x^{2}-30x=\frac{3600}{2}
-60 ni 2 ga bo'lish.
x^{2}-30x=1800
3600 ni 2 ga bo'lish.
x^{2}-30x+\left(-15\right)^{2}=1800+\left(-15\right)^{2}
-30 ni bo‘lish, x shartining koeffitsienti, 2 ga -15 olish uchun. Keyin, -15 ning kvadratini tenglamaning ikkala tarafiga qo‘shing. Ushbu qadam tenglamaning chap qismini mukammal kvadrat sifatida hosil qiladi.
x^{2}-30x+225=1800+225
-15 kvadratini chiqarish.
x^{2}-30x+225=2025
1800 ni 225 ga qo'shish.
\left(x-15\right)^{2}=2025
x^{2}-30x+225 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-15\right)^{2}}=\sqrt{2025}
Tenglamaning ikkala tarafining kvadrat ildizini chiqarish.
x-15=45 x-15=-45
Qisqartirish.
x=60 x=-30
15 ni tenglamaning ikkala tarafiga qo'shish.
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