Consider the following statements: ① the sum of 0 plus a rational number equals the rational number; ② the difference of 0 minus a rational number equals the opposite number of the rational number Consider the following statements: ① 0 plus a rational number, the sum of which is equal to the rational number; ② 0 minus a rational number, the difference is equal to the opposite of the rational number; ③ The product of 0 multiplied by a rational number is 0; ④ The quotient of 0 divided by a rational number is 0 The correct saying is () (A) One (b) two (c) three (d) four

This paper studies the following statements: 1) the sum of 0 plus a rational number equals the rational number; 2) the difference of 0 minus a rational number equals the opposite of the rational number; 3) the product of 0 multiplied by a rational number is 0; 4) the quotient of 0 divided by a rational number is 0

A ^ 2 + B ^ 2 + C ^ 2-ab-6b-6c + 21 = 0, how to find the value of a, B, C

（a-b/2)^2+3/4(b-4)^2+(c-3)^2=0
a=2 b=4 c=3

1 / 15 plus 3 / 49 brackets, a simple operation of multiplying 15-45 by 49
Be comprehensive, don't answer directly, step by step

(1/15+3/49)*15-45/49
=1/15*15+3/49*15-45/49
=1+45/49-45/49
=1

We know the equation x & # 178; + (M + 2) + 2m-1 = 0 about X. we prove that there are two real roots

It is proved that: ∵ X & # 178; + (M + 2) x + 2m-1 = 0 ∵ = (M + 2) # 178; - 4 (2m-1) = M & # 178; + 4m + 4-8M + 4 = M & # 178; - 4m + 4 + 4 = (m-2) # 178; + 4 ∵ (m-2) # 178; ≥ 0 (m-2) # 178; + 4 > 0 ∵ > 0 ∵ X & # 178; + (M + 2) x + 2m-1 = 0 has two real roots

Why divide the area of a triangle by two

The bottom multiplied by height is the area formula of rectangle
The area of the triangle is just half

Cut a 1.2-meter-long cuboid wood into two sections and increase its surface area by 400 square decimeters. What's the volume of the cuboid wood?

If the cube is cut into two sections, then its surface will be added with two surfaces, and the area of one surface is 400 / 2 = 200 square decimeters = 2 square meters
So the cuboid volume is 1.2 * 2 = 2.4 cubic meters

Nine inches plus one inch equals one foot to one foot

If you gain an inch, you will gain an inch

Factorization method 4m ^ 2 + 8MN + 3N ^ 2
Examples of matching methods
x^2+2x4+4^2-4^2+12
=(x-4)^2-4
=(x-4+2)(x-4-2)
=(x-2)(x-6)

Original formula = 4m ^ 2 + 8mn-4n ^ 2-4n ^ 2 + 3N ^ 2
=(2m+2n)^2-n^2
=(2m+2n+n)(2m+2n-n)
=(2m+3n)(2m+n)

The ratio of three fifths to zero point seven is (), () and () can be proportional to it

The ratio is 6 / 7, and then you can find any two ratios that are also 6 / 7 to form a ratio with them. For example: 6, 7.1.8, 2.1, etc

How to solve x square + 5x = 100

X²+5X=100
X²+5X-100 =0
X=(-5±5√17)/2