= 32+0+32x8+32= 32x(1+8+1)=32x10=320

dễ quá

a, A= 1/5.6+1/6.7+1/7.8+...+1/24.25

=1/5-1/6+1/6-1/7+1/7-1/8+...+1/24-1/25

=1/5-1/25

=4/25

hok tốt k nha

a: \(A=\dfrac{1}{5}-\dfrac{1}{6}+\dfrac{1}{6}-\dfrac{1}{7}+...+\dfrac{1}{24}-\dfrac{1}{25}\)

\(=\dfrac{1}{5}-\dfrac{1}{25}=\dfrac{4}{25}\)

b: \(B=\dfrac{1}{3}-\dfrac{1}{5}+\dfrac{1}{8}-\dfrac{1}{19}+\dfrac{1}{19}-\dfrac{1}{32}+\dfrac{1}{32}-\dfrac{1}{57}+\dfrac{1}{57}-\dfrac{1}{87}\)

\(=\dfrac{2}{15}+\dfrac{1}{8}-\dfrac{1}{87}\)

=859/3480

Ta có:\(8^{12}=\left(2^3\right)^{12}=2^{3.12}=2^{36}\\ \\ \\ 32^6=\left(2^5\right)^6=2^{5.6}=2^{30}\) Mà \(2^{36}>2^{30}\)

⇒ Chọn A

8¹² = (2³)¹² = 2³⁶

32⁶ = (2⁵)⁶ = 2³⁰

Vì 2³⁶ > 3³⁰ ⇒ 8¹² > 32⁶ ⇒ Chọn A

32+63 x a x (a x 1-a/1) +32 x 8+32

=32+32x8+32

=32x10

=320

a. (75 + 45) : 5 = ?

Cách 1: (75 + 45) : 5

= 120 : 5 = 24

Cách 2: (75 + 45) : 5

=  75 : 5 + 45 : 5

= 15 + 9

= 24

b.(88 – 32) : 8 = ?

Cách 1: (88 - 32) : 8 

 = 56 : 8 =7

Cách 2: (88 - 32) : 8  

= 88 : 8 – 32 : 8

= 11 – 4

= 7