Two rational numbers whose product is () are reciprocal to each other

Two rational numbers whose product is () are reciprocal to each other

Two rational numbers whose product is (1) are reciprocal to each other

A is a non-zero rational number, its reciprocal and its opposite sum (), the product of which is equal to（

（1）a+1/a+(-a)=1/a
(2)a×1/a×(-a)=-a

A is a non-zero rational number, which is equal to the sum of its reciprocal and their opposite numbers______ The product of these three numbers is equal to_______ .

It's one

Let the equation (x ^ 2 + y ^ 2-25) + a (2x-y-10) = 0, a take any real value, and prove that the circle represented by the equation passes through two points

Only when 2x-y-10 = 0, the value of a has no effect on the equation, so 2x-y-10 = 0 (1) Then the equation is x ^ 2 + y ^ 2-25 = 0 (2) 2x-y-10 = 0 (1) and (2) together, the solution is x = 5, y = 0, or x = 3, y = - 4, so the constant crossing point (5,0), (3, - 4)

Simple calculation of (98 × 128) △ 49

(98×128）÷49
=98×49×128
=2×128
=256

Let a = {x | X & sup2; - 8x + 15 = 0}, B = {x AX-1 = 0}, if B ∈ a, find the set of real number a, and write out all its nonempty proper subsets

A={x|x^2-8x+15=0}={3,5}
B={x|ax-1=0}
B is contained in a
B may = {3,5}, {3}, {5}, empty set
AX-1 = 0 is obviously a linear function,
So, B = {x | AX-1 = 0} = {3} or {5} or empty set
When 3a-1 = 0, = > A = 1 / 3
When 5a-1 = 0, = = > A = 1 / 5
When a = 0, it is an empty set
So: the set of values of real number a = {1 / 3,1 / 5,0}
There are six nonempty proper subsets {0} {1 / 5} {1 / 3} {0,1 / 5} {0,1 / 3} {1 / 3,1 / 5}

A simple method of 0.18 × 2.5 △ 0.18 × 2.5

0.18×2.5÷0.18×2.5
=0.18÷0.18×2.5×2.5
=6.25

F (x) = x ^ 3 + ax ^ 2 + X has maximum and minimum in the interval [- 1,1]. Find the value range of constant a

First of all, there is no problem with this topic. Some people say that f (x) must have extremum on [- 1,1], which is wrong. Extremum must be the point with derivative 0, and f (x) must exist on [- 1,1], which should be the maximum value, not the extremum

Divide the following groups into six fifths, three fifths, four fifths, seven ninths and seven twelfth

The same denominator of 6 / 5 and 4 / 5 is 5, so after general division: 6 / 5, 4 / 5
3 / 10 and 4 / 15, the same denominator is 30, so after the general score: 9 / 30, 8 / 30
7 / 9 and 7 / 12, the same denominator is 36, so 28 / 36, 21 / 36 after general division
Hope to adopt, thank you

Make the image of function y = 2X-4, and answer the following questions according to the image: (1) find the solution set of inequality 2X-4 greater than 0
② Find the solution of the equation 2X-4 = 0. ③ when x takes what value, - 4

The image is a straight line that passes through (0, - 4) and (2,0)
1. The set of X values of the part of the line above the x-axis is the solution set, which is [2, + ∞]
2 the intersection of the line and the x-axis is the solution, x = 2
3 draw a straight line y = 4, and y = - 4, and the intersection point with the known straight line is (4,4), (0, - 4), so the value of X is 0