1. Under what conditions, the value of fraction 2x-5 / X & # 178; + 4 is negative. 2. The meaningful condition of fraction X-1 / X - 2 is__________ The meaningless condition is____________ The value is zero if______________ ?

1. Under what conditions, the value of fraction 2x-5 / X & # 178; + 4 is negative. 2. The meaningful condition of fraction X-1 / X - 2 is__________ The meaningless condition is____________ The value is zero if______________ ?

﹙1﹚∵x²＋4＞0
And (2x-5) / (X & # 178; + 4) ＜ 0
∴ 2x－5＜0
x＜5/2.
(2) the meaningful conditions of (x-1) / (|x-2) are: |x-2 ≠ 0, X ≠ ± 2;
The meaningless condition is: | x | - 2 = 0, x = ± 2
The condition of 0 is: X-1 = 0, x = 1

Ask some eighth grade math fraction questions, some please give some
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The results show that there are 48 students in class A and 45 students in class B. the pass rate of class A is 21% higher than that of class B. It is known that there are 110 students in class A and class B

(a+ba−b)2•2a−2b3a+3b-a2a2−b2÷ab

The original formula = (a + b) 2 (a − b) 2 × 2 (a − b) 3 (a + b) - A2 (a + b) (a − b) × Ba = 2 (a + b) 3 (a − b) - AB (a + b) (a − b) = 2 (a + b) 2 − 3ab3 (a + b) (a − b) = 2A2 + AB + 2b23 (a + b) (a − b). So the answer is 2A2 + AB + 2b23 (a + b) (a − b)

Find mathematics people's education press on the third day of the problem is the fractional inverse proportion function data Pythagorean theorem of the best answer is urgent

1、 Pythagorean Theorem 1. In the following arrays, the triangles that can not be regarded as the length of three sides of a right triangle are () a.9,12,15 b.7,24,25 c.6,8,10 d.3,5,7 2. After reducing or expanding all sides of a right triangle by the same multiple, the triangle () A. may be an acute triangle B. may not be a right triangle