maths problems

[匿名]

2014-08-21 6:25 pm

------------------.------
1)Express 0.35 in the form of a/b, where a and b are integers.

2)Solve 9^x= 1/(4√27).

3)Evaluate [5(10^2011)+6(10^2010)]/4[10^(-2012)].

Need Steps, Plz.

更新1:

. 0.35

更新2:

the point is on the 5

回答 (1)

用戶2053

2014-08-21 10:30 pm

✔ 最佳答案

1)
--- .
0.35 = a/b
------- .--------- .
10(0.35) - 0.35 = 10(a/b) - a/b
-- .-------- .
3.5 - 0.35 = 9a/b
3.5 - 0.3 = 9a/b
3.2 = 9a/b
32/90 = a/b
a/b = 16/45

2)9ˣ = 1/∜27
3²ˣ = ∜(1/3³)
3²ˣ = ∜3⁻³
3²ˣ = 3⁻³ˡ ⁴
2x = - 3/4
x = - 3/8

3)
5(10²º¹¹) + 6(10²º¹º)
────────────
　　4(10⁻²º¹²)=5(10²º¹¹⁺²º¹²) + 6(10²º¹º⁺²º¹²)
──────────────────
　　　　　　4= 5(10⁴º²³) + 6(10⁴º²²)
──────────────
　　　　 4
= (10⁴º²²) (50 + 6) / 4= 14(10⁴º²²)= 1.4 × 10⁴º²³

👍 0 👎 0