1. A pile of coal, originally planned to use 1.5 tons per day, can use 30 days If 0.25 tons of coal can be saved every day, how many days can this pile of coal be used? 2. On a 1:30000000 map, the distance between Beijing and Guangzhou is 7cm. How many kilometers is the actual distance between Beijing and Guangzhou?

1. A pile of coal, originally planned to use 1.5 tons per day, can use 30 days If 0.25 tons of coal can be saved every day, how many days can this pile of coal be used? 2. On a 1:30000000 map, the distance between Beijing and Guangzhou is 7cm. How many kilometers is the actual distance between Beijing and Guangzhou?

1. A pile of coal, originally planned to use 1.5 tons per day, can be used for 30 days. (using proportional solution) if you can save 0.25 tons of coal per day, how many days can this pile of coal be used?
Suppose this pile of coal can last X days
(1.5-0.25)x=1.5×30
x=45÷1.25
x=36
This pile of coal will last 36 days
2. On a 1:30000000 map, the distance between Beijing and Guangzhou is 7cm. How many kilometers is the actual distance between Beijing and Guangzhou?
Method 1: 7 △ (1 / 30000000) = 210000000cm = 2100km
Method 2: the actual distance between Beijing and Guangzhou is about x cm
7：x=1：30000000
x=210000000
210000000 cm = 2100 km
The actual distance between Beijing and Guangzhou is about 2100km

Solving equation 1.2x = 4.8

How to solve the equation 2x + 4 times 3.2 = 40.8

2x+4×3.2=40.8
2x=40.8-12.8
2x=28
x=14

0.2x △ 1.8 = 3 solutions

0.2x÷1.8=3
0.2x=3×1.8
0.2x=5.4
x=5.4÷0.2
x=27

Solve the equation; 4 (2x + 3) + 5 (2x + 3) = 8 (2x + 3) - 1

4（2x+3）+5（2x+3）=8（2x+3）-1 8X+12+10X+15=16X+24-1 18X-16X=24-12-15-1 2X=-4 X=-2

How to solve the equation with 1.2x + 0.8 × (32-x) = 32.8

1.2X+0.8×（32-X）=32.8
x=18

How to solve the equation with 32 / 8-32 / 2x = 1.6 * 0.5

Simplifying the original equation
4-16/x=1.6^0.5
Multiply both sides by X
4x-16=1.6^0.5x
（4-1.6^0.5）*x=16
x=16/（4-1.6^0.5）
The calculator worked it out
x=5.84990118229706

Solve the equation 12:3 = 2x 16.8:32 = 24: X

The first formula: 4 = 2x / 3, we can get x = 4 * 3 / 2 = 6
The second formula: x = (32 * 24) / 16.8, x = 45.71

Solving equation 2 ^ 2x + 1 = 8

2^2x+1=8
2^2x+1=2^3
2x+1=3
x=1

Solve the equation with proper method: 2x ^ 2 + X-5 = 0; (2-1) (x-3) = 8

2x²+x-5=0
x²+x/2=5/2
x²+x/2+1/16=5/2+1/16
(x+1/4)²=41/16
x+1/4=±√41/4
x=(-1-√41)/4,x=(-1+√41)/4
（2x-1)(x-3)=8
x²-7x/2+49/16=5/2+49/16
(x-7/4)²=89/16
x-7/4=±√89/16
x=(7-√89)/4,x=(7+√89)/4