Mary likes music

Mary likes music

Marie likes music
Hope to adopt it

If the values of 4N + 8 and 3n-10 are opposite to each other, then n = ()
A. -18B. 187C. −187D. 27

According to the meaning of the question: 4N + 8 + 3n-10 = 0, transfer and merge: 7n = 2, solution: n = 27

If 3 / 4 of a is equal to 2 / 3 of B, then a < B

Wrong,
3/4 a=2/3 b
A / b = 8 / 9
That is, a: B = 8:9
If a > 0, b > 0, then a

If 4x = 3x + 7, what is the reason for 4x - () = 7

4x-(3x)+7
The reason is that by subtracting 3x from both sides of the equation, the equation still holds

1 + 2 + 3 + 4 + 5 +. + 1978 + 1979 + 1978 + 1977 +. + 2 + 1 / 1978 * 1979 + 1979 * 1980

Molecular formula = (1978 + 1980) * 1979
Original denominator = (1 + 1978) * 1978 / 2 + 1979
The original formula is 2

The relationship between ABC and function in mathematical quadratic function
How to judge the positive and negative of ABC a + B + C A-B + C 4a-2b + C 4A + 2B + 2C,

Sum the six numbers 5, 555555555

To simplify the algorithm:
5=1*5
55=5*11
555=5*111
5555=5*1111
55555=5*11111
555555=5*111111
So 5 + 55 + 555 + 5555 + 55555 = 5 * (1 + 11 + 111 + 1111 + 11111 + 111111) = 617280

Given the function f (x) = log2 (1 / x + 1), x > 0 and (1 / 2) ^ X-1, XF (a), what is the value range of a?
To answer in detail, give high marks

F (x) = log2 [1 / (x + 1)], X ≥ 0, f (x) = (1 / 2) ^ X - 1, x < 0, when x ≥ 0, ∵ x + 1 monotonically increases, ∵ 1 / (x + 1) monotonically decreases, ∵ f (x) = log2 (1 / (x + 1)) monotonically decreases, when x = 0, the maximum value f (0) = log2 [1 / (0 + 1)] = 0, when XF (a) ∵ 3-2a ^ 2 < a ∵ 2A ^ 2 + A-3 > 0, that is (2a + 3) (A-1) > 0