Bài 3:
a: 71-(33+x)=26
=>x+33=71-26=45
=>x=45-33
=>x=12
b: (x+73)-26=76
=>x+73=26+76
=>x+73=102
=>x=102-73
=>x=29
c: 89-(73-x)=20
=>73-x=89-20=69
=>x=73-69
=>x=4
d: 198-(x+4)=120
=>x+4=198-120=78
=>x=78-4
=>x=74
e: \(9^{x-1}=9\)
=>x-1=1
=>x=2
\(x^4=16\)
=>\(x^4=2^4\)
=>x=2 hoặc x=-2
f: x+(-23)=-45
=>x-23=-45
=>x=-45+23
=>x=-22
g: 3x-46=-52
=>3x=-52+46
=>3x=-6
=>x=-2
h: -34-4x=-22
=>4x+34=22
=>4x=22-34=-12
=>x=-3
i: -25+3(x-8)=-34
=>3(x-8)=-34+25=-9
=>x-8=-3
=>x=-3+8=5
j: \(\left(-3\right)^2+5x=-1\)
=>5x+9=-1
=>5x=-1-9
=>5x=-10
=>x=-2
Bài 6:
a:
\(40=2^3\cdot5;24=2^3\cdot3\)
=>ƯCLN(40;24)=\(2^3=8\)
=>ƯC(40;24)=Ư(8)={1;-1;2;-2;4;-4;8;-8}
\(24=2^3\cdot3;36=2^2\cdot3^2;60=2^2\cdot3\cdot5\)
=>ƯCLN(24;36;60)=\(2^2\cdot3=12\)
=>ƯC(24;36;60)=Ư(12)={1;-1;2;-2;3;-3;4;-4;6;-6;12;-12}
b: \(25=5^2;30=2\cdot3\cdot5\)
=>BCNN(25;30)=\(2\cdot3\cdot5^2=6\cdot25=150\)
=>BC(25;30)=B(150)={150;300;450;...}
\(80=2^4\cdot5;60=2^2\cdot3\cdot5\)
=>BCNN(80;60)=\(2^4\cdot3\cdot5=16\cdot15=240\)
=>BC(80;60)=B(240)={240;480;720;...}
