Question

giúp mk với mk cần gấp lắm

1.Tìm x

a)108 - 4 (3x + 5) = 8⁶ : 8⁴

^{b)2448 :[119 - (x - 6) = 24}

^2.Tìm

a) ƯCLN,BCNN (24,60,50)

 

b) BCNN (168;90;140)

 

Answer 1

a) 108-4(3x+5)=\(8^6:8^4\)

=>108-4(3x+5)=\(8^2\)

=> 108 -12x-20=64

=>88-12x=64

=>12x=88-64

=>12x=24

=> x=2

b)\(2448∶[119-(x-6)]=24\)

=>\([119-(x-6)]=102 \)

=>\((x-6)=119-102=17\)

=>\(x=17+6=23\)

Bài 2:

a) Ta có: 24=\(2^3.3\)

\(60=2^2.3.5 \) \(50=2.5^2\)

=> UCLN(24;60;50)=2

=>BCNN(24;60;50)=\(2^3.5^2.3=600\)

b) Ta có: 168=\(2^3.3.7\)

\(90=2.3^2.5\) \( 140=2^2.5.7\)

=>BCNN(168;40;140)=\(2^3.3^2.5.7=2520\)