Ngọc Lan Nguyễn
Giới thiệu về bản thân
\(125\cdot30+250\cdot33+125\cdot4\\ =125\cdot30+125\cdot\left(2\cdot33\right)+125\cdot4\\ =125\cdot30+125\cdot66+125\cdot4\\ =125\cdot\left(30+66+4\right)\\ =125\cdot100\\ =12500\)
\(\left(x-3\right)^6=\left(x-3\right)^4\\ \Leftrightarrow\left(x-3\right)^6:\left(x-3\right)^4=\left(x-3\right)^4:\left(x-3\right)^4\\ \Leftrightarrow\left(x-3\right)^2=\left(x-3\right)^0\\ \Leftrightarrow\left(x-3\right)^2=1\\ \Leftrightarrow\left(x-3\right)^2=1^2\\ \Leftrightarrow x-3=1\\ \Leftrightarrow x=1+3=4\)
Vậy \(x=4\) thỏa mãn bài toán.
5 x (5 - 5 + 5) : 5 = 5
Ta có: \(\dfrac{x}{4}=\dfrac{y}{3}\) và \(xy=12\)
\(\Leftrightarrow3x=4y\)
\(\Leftrightarrow x=\dfrac{4}{3}y\)
\(\Rightarrow xy=\dfrac{4}{3}y\cdot y=12\)
\(\Leftrightarrow y\cdot y=12:\dfrac{4}{3}\)
\(\Leftrightarrow y^2=12\cdot\dfrac{3}{4}\)
\(\Leftrightarrow y^2=9\)
\(\Leftrightarrow y^2=3^2\)
\(\Leftrightarrow y=3\)
\(\Rightarrow x=12:y=12:3=4\)
Vậy x = 4 và y = 3.
\(2^{x-2}=64\)
\(\Leftrightarrow2^{x-2}=2^6\)
\(\Leftrightarrow x-2=6\)
\(\Leftrightarrow x=6+2\)
\(\Leftrightarrow x=8\)
Vậy \(x=8\).
\(x^2-4=0\)
\(\Leftrightarrow x^2=0+4\)
\(\Leftrightarrow x^2=4\)
\(\Leftrightarrow x^2=2^2\) hoặc \(x^2=\left(-2\right)^2\)
\(\Leftrightarrow x=2\) hoặc \(x=-2\)
Vậy \(x=2\) hoặc \(x=-2\).
free/ He/ most/ time/ sports/ spends/ of/ his/ playing/.
==> He spends his most of free time playing sports.
\(5^{40}\cdot125^2\cdot625^3\)
\(=5^{40}\cdot\left(5^2\cdot5^2\cdot5^2\right)\cdot\left(5^3\cdot5^3\cdot5^3\cdot5^3\right)\)
\(=5^{40}\cdot5^6\cdot5^{12}\)
\(=5^{46}\cdot5^{12}\)
\(=5^{58}\)
Vậy \(5^{40}\cdot125^2\cdot625^3=5^{58}\).