\(2017-\left\{5^2x2^2-11\left[7^2-5x2^3+8\left(11^2-121\right)\right]\right\}\)
giúp mk nha ! thank you nhìu nhìu
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
a) Câu này đề chưa rõ rành lắm nên mk k làm nhé.
b) Đặt \(A=1+3+3^2+3^3+...+3^{100}\)
\(\Rightarrow3A=3+3^2+3^3+3^4+...+3^{101}\)
\(\Rightarrow3A-A=\left(3+3^2+3^3+...+3^{101}\right)-\left(1+3+3^2+3^3+...+3^{100}\right)\)
\(\Rightarrow2A=3^{101}-1\)
\(\Rightarrow A=\frac{3^{101}-1}{2}\)
a) \(\frac{2015x\left(1-\frac{1}{2016}+\frac{1}{2017}\right)}{5x\left(1-\frac{1}{2016}+\frac{1}{2017}\right)}\)
\(=\frac{2015x}{5x}\)
\(=\frac{2015}{5}=403\)
\(1000-\left\{\left(-5\right)^3.\left(-2\right)^3-11.[7^2-5.2^3+8.\left(11^2-121\right)]\right\}\)
=\(1000-\left\{[\left(-5\right).\left(-2\right)]^3-11.[7^2-5.2^3+2^3.\left(11^2-11^2\right)]\right\}\)
= \(1000-\left\{1000-11.[7^2-2^3.\left(5+0\right)]\right\}\)
= \(1000-[1000-11.\left(7^2-2^3.5\right)\)
= \(1000-[1000-11.\left(49-40\right)]\)
= \(1000-\left(1000-11.9\right)\)
= \(1000-\left(1000-99\right)=1000-1000+99\)
= 0 + 99 = 99
a) \(\frac{x-6}{7}+\frac{x-7}{8}+\frac{x-8}{9}=\frac{x-9}{10}+\frac{x-10}{11}+\frac{x-11}{12}\)
=> \(\left(\frac{x-6}{7}+1\right)+\left(\frac{x-7}{8}+1\right)+\left(\frac{x-8}{9}+1\right)=\left(\frac{x-9}{10}+1\right)+\left(\frac{x-10}{11}+1\right)+\left(\frac{x-11}{12}+1\right)\)
=> \(\frac{x+1}{7}+\frac{x+1}{8}+\frac{x+1}{9}-\frac{x+1}{10}-\frac{x+1}{11}+\frac{x+1}{12}=0\)
=> \(\left(x+1\right)\left(\frac{1}{7}+\frac{1}{8}+\frac{1}{9}-\frac{1}{10}-\frac{1}{11}-\frac{1}{12}\right)=0\)
=> x + 1 = 0
=> x = -1
b) \(\frac{x-1}{2020}+\frac{x-2}{2019}-\frac{x-3}{2018}=\frac{x-4}{2017}\)
=> \(\left(\frac{x-1}{2020}-1\right)+\left(\frac{x-2}{2019}-1\right)-\left(\frac{x-3}{2018}-1\right)=\left(\frac{x-4}{2017}-1\right)\)
=> \(\frac{x-2021}{2020}+\frac{x-2021}{2019}-\frac{x-2021}{2018}=\frac{x-2021}{2017}\)
=> \(\left(x-2021\right)\left(\frac{1}{2020}+\frac{1}{2019}-\frac{1}{2018}-\frac{1}{2017}\right)=0\)
=> x - 2021 = 0
=> x = 2021
c) \(\left(\frac{3}{4}x+3\right)-\left(\frac{2}{3}x-4\right)-\left(\frac{1}{6}x+1\right)=\left(\frac{1}{3}x+4\right)-\left(\frac{1}{3}x-3\right)\)
=> \(\frac{3}{4}x+3-\frac{2}{3}x+4-\frac{1}{6}x-1=\frac{1}{3}x+4-\frac{1}{3}x+3\)
=> \(-\frac{1}{12}x+6=7\)
=> \(-\frac{1}{12}x=1\)
=> x = -12
\(A=1500-\left\{5^3.2^3-11.\left[7^2-5.2^3+8\left(11^2-121\right)\right]\right\}\)
\(A=1500-\left\{125.8-11.\left[49-5.8+8\left(121-121\right)\right]\right\}\)
\(A=1500-\left\{1000-11\left[49-40+8.0\right]\right\}\)
\(A=1500-\left\{1000-11.9\right\}\)
\(A=1500-\left\{1000-99\right\}\)
\(A=1500-901=599\)
Pt tương đương:
\(2x^2+3\left(x^2-1\right)=5x^2+5x\)
\(\Leftrightarrow2x^2+3x^2-3=5x^2+5x\)
\(\Leftrightarrow5x=-3\)
\(\Leftrightarrow x=-\frac{3}{5}\)
Vậy pt có nghiệm là :\(x=-\frac{3}{5}\)
Đề là \(\lim\limits_{x\rightarrow3}\dfrac{f\left(x\right)-5}{x-3}\) hay \(\lim\limits_{x\rightarrow3}\dfrac{f\left(x\right)-15}{x-3}\) em?
\(\dfrac{f\left(x\right)-5}{x-3}\) thì giới hạn bên dưới ko phải dạng vô định, kết quả là vô cực
\(2017-\left\{5^2.2^2-11\left[7^2-5.2^3+8\left(11^2-121\right)\right]\right\}\)
Đặt : \(A=2017-\left\{5^2.2^2-11\left[7^2-5.2^3+8\left(11^2-121\right)\right]\right\}\)
\(A=2017-\left\{25.4-11\left[49-5.8+8\left(121-121\right)\right]\right\}\)
\(A=2017-\left\{25.4-11\left[49-5.8+0\right]\right\}\)
\(A=2017-\left\{25.4-11\left[49-40\right]\right\}\)
\(A=2017-\left\{25.4-11.9\right\}\)
\(A=2017-\left\{25.4-99\right\}\)
\(A=2017-\left\{100-99\right\}\)
\(A=2017-1=2016\)
Vậy A = 2016