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a.(3^2+4^2).x=10^2
(9+16).x =100
25.x =100
x =100:25
x =4
b.(x-5)^2 =81
x-5 =9
x =9+5
x =14
c.(2x+1)^3 = 343
2x+1 = 7
2x =7-1
2x =6
x =6:2
x = 3
a)\(x^{15}=x\Rightarrow x\in\left\{0;1\right\}\) d)Là ý b
b)\(\left(2x+1\right)^3=125\\ \left(2x+1\right)^3=5^3\Rightarrow2x+1=5\\ 2x=4\\ x=2\) e)\(\left(x-3\right)^2=25\\ \Rightarrow\left(x-3\right)^2=5^2\\ \Rightarrow\hept{\begin{cases}x-3=5\Rightarrow x=8\\x-3=-5\Rightarrow x=-2\end{cases}}\)
c)\(\left(x-5\right)^4=\left(x-5\right)^6\\ \Rightarrow x-5\in\left\{0;1\right\}\Rightarrow x\in\left\{5;6\right\}\)
\(D=\) \(\frac{11.3^{22}.3^7-9^{15}}{\left(2.3^{14}\right).2}\)
\(=\) \(\frac{11.3^{22+7}-\left(3^2\right)^{15}}{2^2.\left(3^{14}\right)^2}\)
\(=\) \(\frac{11.3^{29}-3^{30}}{4.3^{28}}\)
\(=\) \(\frac{11.3^{29}-3^{29}.3}{4.3^{28}}\)
\(=\) \(\frac{3^{29}\left(11-3\right)}{3^{28}.4}\)
\(=\) \(\frac{3^{28}.3.8}{3^{28}.4}\)
\(=\) \(\frac{3^{28}.3.4.2}{3^{28}.4}\)
\(=\) \(6\)
Chúc bn hok tốt ~
\(D=\frac{11.3^{22}.3^7-9^{15}}{\left(2.3^{14}\right).2}\)
\(=\frac{11.3^{22+7}-\left(3^2\right)^{15}}{2^2.\left(3^{14}\right)^2}\)
\(=\frac{11.3^{29}-3^{30}}{4.3^{28}}\)
\(=\frac{11.3^{29}-3^{29}.3}{4.3^{28}}\)
\(=\frac{3^{29}\left(11-3\right)}{3^{28}.4}\)
\(=\frac{3^{28}.3.8}{3^{28}.4}\)
\(=\frac{3^{28}.3.4.2}{3^{28}.4}=6\)
1) + S = 5 + 52 + 53 + ... + 596 (có 96 số; 96 chia hết cho 6)
S = (5 + 52 + 53 + 54 + 55 + 56) + (57 + 58 + 59 + 510 + 511 + 512) + ... + (591 + 592 + 593 + 594 + 595 + 596)
S = (5 + 54) + (52 + 55) + (53 + 56) + (57 + 510) + ... + (593 + 596)
S = 5.(1 + 53) + 52.(1 + 52) + 53.(1 + 53) + 57.(1 + 53) + ... + 593.(1 + 53)
S = 5.126 + 52.126 + 53.126 + 57.126 + ... + 593.126
S = 126.(5 + 52 + 53 + 57 + ... + 593) chia hết cho 126
+ Do 5 + 52 + 53 + 57 + ... + 593 chia hết cho 5 mà 126 chia hết cho 2
=> S chia hết cho 10 => S có tận cùng là 0
2) 162008 - 82000
= (...6) - (84)500
= (...6) - (...6)500
= (...6) - (...6)
= (...0) chia hết cho 10
3) 13 + 23 + 33 + 43 + 53 + 63 + 73 + 83 + 93 + 103 = (x + 12)2
=> 1 + 8 + 27 + 64 + 125 + 216 + 343 + 512 + 729 + 1000 = (x + 1)2
=> (1 + 729) + (8 + 512) + (27 + 343) + (64 + 216) + 125 + 1000 = (x + 1)2
=> 730 + 520 + 370 + 280 + 1125 = (x + 1)2
=> (730 + 370) + (520 + 280) + 1125 = (x + 1)2
=> 1100 + 800 + 1125 = (x + 1)2
=> 3025 = (x + 1)2, vô lí
1) + S = 5 + 52 + 53 + ... + 596 (có 96 số; 96 chia hết cho 6)
S = (5 + 52 + 53 + 54 + 55 + 56) + (57 + 58 + 59 + 510 + 511 + 512) + ... + (591 + 592 + 593 + 594 + 595 + 596)
S = (5 + 54) + (52 + 55) + (53 + 56) + (57 + 510) + ... + (593 + 596)
S = 5.(1 + 53) + 52.(1 + 52) + 53.(1 + 53) + 57.(1 + 53) + ... + 593.(1 + 53)
S = 5.126 + 52.126 + 53.126 + 57.126 + ... + 593.126
S = 126.(5 + 52 + 53 + 57 + ... + 593) chia hết cho 126
+ Do 5 + 52 + 53 + 57 + ... + 593 chia hết cho 5 mà 126 chia hết cho 2
=> S chia hết cho 10 => S có tận cùng là 0
a) \(\left(x-2\right)^2=2^2\)
\(\Rightarrow\left(x-2\right)\left(x-2\right)=2^2\Rightarrow x^2-4x+4=4\)
\(\Rightarrow x^2-4x=0\Rightarrow x\left(x-4\right)=0\Rightarrow\orbr{\begin{cases}x=0\\x-4=0\end{cases}}\Rightarrow\orbr{\begin{cases}x=0\\x=4\end{cases}}\)
b) \(\left(x+\frac{1}{2}\right)^2=16\)
\(\Rightarrow\left(x+\frac{1}{2}\right)^2=4^2=\left(-4\right)^2\)
\(x+\frac{1}{2}=4\) hoặc \(x+\frac{1}{2}=-4\)
\(\Rightarrow x=4-\frac{1}{2}\) hoặc \(x=-4-\frac{1}{2}\)
\(\Rightarrow x=\frac{7}{2}\) hoặc x = \(-\frac{9}{2}\)
c) \(\left(2x-3\right)^2-9=27\Rightarrow\left(2x-3\right)^2=36\)
\(\Rightarrow2x-3=6\) hoặc \(2x-3=-6\)
\(\Rightarrow2x=9\) hoặc \(2x=-3\)
\(\Rightarrow x=\frac{9}{2}\) hoặc \(x=-\frac{3}{2}\)
d) \(\left(2x-3\right)^3=-8\Rightarrow2x-3=-2\)
\(\Rightarrow2x=-2+3=1\Rightarrow x=\frac{1}{2}\)
Chúc bạn hc giỏi,lila ma ri !