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Bài 1 : Bài giải
a) \(942^{60}-357^{37}=942^{60}-357^{36}\cdot357=\left(942^4\right)^{15}-\left(357^4\right)^9\cdot357=\overline{\left(...6\right)}^{15}-\overline{\left(...1\right)}^9\cdot357\)
\(=\overline{\left(...6\right)}-\overline{\left(...1\right)}\cdot357=\overline{\left(...6\right)}-\overline{\left(...7\right)}=\overline{\left(...9\right)}\text{ }⋮̸\text{ }5\)
\(\Rightarrow\text{ Đề sai}\)
a ) số đối : -9 = 9 ; 17 = 17
b ) 63 = 216 ; 70 = 1
Bài 2 :
a) 42
b) 30
c) 3800
Bài 3 :
a) x = -31
b) x = 2
c) x = { -2 ;-1 ; 0 ;1;2;3;4 }
1/a.9;-17.
b.216;1
2/a.42;b.30;c.3800
3/a.x=-31;b.x=2;c.x=-2;-1;0;1;2;3;4.
Bài 1:
a) 23=2.2.2=823=2.2.2=8;
24=23.2=8.2=1624=23.2=8.2=16;
25=24.2=16.2=3225=24.2=16.2=32;
26=25.2=32.2=6426=25.2=32.2=64;
27=26.2=64.2=12827=26.2=64.2=128;
28=27.2=128.2=25628=27.2=128.2=256;
29=28.2=256.2=51229=28.2=256.2=512;
210=29.2=512.2=1024210=29.2=512.2=1024
b) 32=3.3=932=3.3=9;
33=32.3=9.3=2733=32.3=9.3=27;
34=33.3=27.3=8134=33.3=27.3=81;
35=34.3=81.3=24335=34.3=81.3=243.
c) 42=4.4=1642=4.4=16;
43=42.4=16.4=6443=42.4=16.4=64;
44=43.4=64.4=25644=43.4=64.4=256.
d) 52=5.5=2552=5.5=25;
53=52.5=25.5=12553=52.5=25.5=125;
54=53.5=125.5=62554=53.5=125.5=625.
e) 62=6.6=3662=6.6=36;
63=62.6=36.6=21663=62.6=36.6=216;
64=63.6=216.6=129664=63.6=216.6=1296.
Bài giải
a) Ta có: A = 550 - 548 + 546 - 544 +...+ 56 - 54 + 52 - 1
=> A = (550 - 548) + (546 - 544) +...+ (56 - 54) + (52 - 1)
=> A = (548.52 - 548.1) + (544.52 - 544.1) +...+
(54.52 - 54.1) + 50.(52 - 1)
=> A = 548.(52 - 1) + 544.(52 - 1) +...+ 54.(52 - 1) +
50.(52 - 1)
=> A = (52 - 1).(548 + 544 +...+ 54 + 50)
Bài 1 :
\(2^x.8=512\)
\(2^x=512:8\)
\(2^x=64\)
\(2^x=2^6\)
\(\Rightarrow x=6\)
\(b,\left(2x+1\right)^3=125\)
\(\left(2x+1\right)^3=5^3\)
\(\Rightarrow2x+1=5\)
\(\Rightarrow2x=4\)
\(\Rightarrow x=2\)
\(c,x^{20}=x\)
\(\Rightarrow\orbr{\begin{cases}x=0\\x=1\end{cases}}\)
\(d,\left(x-3\right)^{10}=0\)
\(\Rightarrow x-3=0\)
\(\Rightarrow x=3\)