Solve the equation 12x-9x = 8.1

Solve the equation 12x-9x = 8.1

3x=8.1,x=8.1/3=2.7

How to solve the equation that 9x plus 2.5 equals 2.5

9x+2.5=2.
9x=0
x=0

1、 13.2x + 9x = 33.3 2.13 (x + 5) = 169 3.3 (x + 2.1) = 10.5
1、 13.2x + 9x = 33.3
2、 13 (x + 5) = 169
3、 3 (x + 2.1) = 10.5
4、 12x-9x = 8.7
5、 1.5 (x + 1.6) = 3.6
6、 2 (x-3) = 5.8
7、 3.4x-48 = 26.8
8、 4.2x + 2.5 = 134

（1）×＝1.5
（2）×＝8
（3）×＝1.4
（4）×＝2.9
（5）×＝0.8
（6）×＝5.9
（7）×＝12
（8）×＝31.3

(A2 + 2Ab + B2) - (a2-2ab + B2) simplification

=a²+2ab+b²-a²+2ab-b²
=4ab

As shown in the figure, it is known that ad is the height of triangle paper ABC. Fold the paper along the straight line EF to make point a coincide with point D. verify that EF is parallel to BC. Baidu is wrong

It is proved that the ∵ line EF is the symmetry axis of line ad,
∴EF⊥AD,
∵AD⊥BC,
In plane, two lines perpendicular to AD are parallel to each other

How many tons is 30 tons and 40 kg

30.04

The length of the playground is 50 meters and the width is 30 meters. If the length is expanded to 100 meters and the width remains unchanged, how many times will the playground be expanded?

50*30=1500
100*30=3000
3000/1500=2

The girth of isosceles triangle is 10 cm, one side is 3 cm, and the other sides are?

Two answers
Because the two sides of an isosceles triangle are equal
The length of one side is 3, which may be waist length or bottom length,
If it is waist length, the other two sides are 3 and 4 respectively;
If it is the bottom length, the other two sides are 3.5 and 3.5 respectively

In the labor class, it took Xiaofang a fifth of an hour to clean an area of 8 square meters. How many hours does it take for her to clean an area of 16 square meters
Trouble answer must be accurate, urgent!

(1 / 5) × 16 △ 8 = 2 / 5 (hours)
Two fifths of an hour

Each graph as shown in the figure represents a triangle shaped pattern composed of several potted flowers. Each side (including two vertices) has n (n > 1) potted flowers. The total number of potted flowers in each pattern is s. according to this rule, the quadratic equation with s and N as unknowns is s______ ．

According to the shape of the triangle formed by the pattern, its perimeter is equal to three times of the side length, but because each vertex is repeated once, so s = 3n-3