\(4.15⋮3;5\)

\(7.45⋮3;5\)

11.7 không chia hết cho 3 và 5

Lời giải:
\(\frac{20^4.15^5}{12^5.25^4}=\frac{(2^2.5)^4.(3.5)^5}{(2^2.3)^5.(5^2)^4}=\frac{2^8.5^4.3^5.5^5}{2^{10}.3^5.5^8}\)

\(=\frac{2^8.5^9.3^5}{2^{10}.3^5.5^8}=\frac{2^8.5^8.5.3^5}{2^8.2^2.3^5.5^8}=\frac{5}{2^2}=\frac{5}{4}\)

2,07+ 4,15 +17,93 +5,85= 30

2,07 + 4,15 + 17,93 + 5,85

= ( 2,07 + 17,93 ) +  ( 4,15 + 5,85 )

=20 + 10

=30

tính sao bạn

ko phải đâu, - 80 đấy bạn

Theo đầu bài ta có:
\(S=1\cdot6+2\cdot9+3\cdot12+4\cdot15+...+98\cdot297+99\cdot300\)
\(=1\cdot\left(2\cdot3\right)+2\cdot\left(3\cdot3\right)+...+98\cdot\left(99\cdot3\right)+99\cdot\left(100\cdot3\right)\)
\(=1\cdot2\cdot3+2\cdot3\cdot\left(4-1\right)+...+98\cdot99\cdot\left(100-97\right)+99\cdot100\cdot\left(101-98\right)\)
\(=1\cdot2\cdot3+2\cdot3\cdot4-1\cdot2\cdot3+...+98\cdot99\cdot100-97\cdot98\cdot99+99\cdot100\cdot101-98\cdot99\cdot100\)
\(=99\cdot100\cdot101\)
\(=999900\)

\(\dfrac{8^4.15^4}{12^3.10^3}=\dfrac{2^{12}.3^4.5^4}{2^6.3^3.2^3.5^3}=2^3.3.5=120\)

Vì \(-\left|2x+3\right|\le0\Rightarrow4-\left|2x+3\right|\le4\)

\(\Rightarrow A\le4\forall x\)

Dấu "=" xảy ra khi \(\left|2x+3\right|=0\Rightarrow2x+3=0\)

\(\Rightarrow x=\dfrac{-3}{2}\)

Vậy \(MAX_A=A\) khi x = -3/2.

a: \(625\cdot8=5^4\cdot2^3\)

b: \(9^4\cdot15^2=3^{10}\cdot5^2\)

104 - 4 * 15 + (-45) = -1

Chúc bạn học tốt!

^_^

104 - 4.15 + (-45)

=104 - 60 + (-45)

= 44 + ( - 45)

= - 1