A batch of coal was transported to a factory. Originally, it was planned to burn 0.5 tons of coal per day for 30 days. In fact, it burned 10 days more. How many tons per day?

A batch of coal was transported to a factory. Originally, it was planned to burn 0.5 tons of coal per day for 30 days. In fact, it burned 10 days more. How many tons per day?

Let x tons be burned every day, 0.5 × 30 = (30 + 10) x, & nbsp; & nbsp; & nbsp; 15 = 40x, & nbsp; 15 △ 40 = 40x △ 40, & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; & nbsp; x = 0.375, a: 0.375 tons per day

A batch of coal was delivered to a canteen. It was originally planned to burn 0.6 tons of coal every day, which can be burned for 30 days. After the improvement of the stove, this batch of coal can be burned for 6 days more. After the improvement of the stove, how many tons of coal will be burned less every day

It was originally planned to burn 0.6 tons per day for 30 days
Therefore, 0.6 * 30 of coal is 18 tons
After the improvement of the stove, this batch of coal can be burned for another 6 days, that is, 30-6 = 24 days
After the improvement of the stove, the daily coal consumption is reduced by 18 / 24 = 0.75 tons

The canteen transported a batch of coal, which was originally planned to burn 0.16 tons per day, and could burn for 30 days. In fact, it saved 20% per day compared with the plan
5、 How many days can this coal actually burn?

0.16×30÷[0.16×(1-25%)]
=30÷0.75
=40 days
The coal can actually burn for 40 days

How to solve x ^ 2-3x-1 = 12 / (x ^ 2-3x)
RT

Let x ^ 2-3x = t solution get t = 4 or T = - 3 x ^ 2-3x = 4 solution get X1 = - 1 x2 = 4 x ^ 2-3x = - 3 no solution, so the solution of the original equation is X1 = - 1 x2 = 4

Xsquare-3x-1 = 12 / (xsquare-3x)
solve equations

Let a = x & sup2; - 3x
a-1=12/a
a²-a-12=0
(a-4)(a+3)=0
a=4,a=-3
x²-3x=4
x²-3x-4=(x+1)(x-4)=0
x=-1,x=4
x²-3x=-3
x²-3x+3=0
If the discriminant is less than 0, there is no solution
So x = - 1, x = 4

3x+12×6=120

3x+12×6=120
3x+72=120
3x=120-72
3x=48
x=48÷3
x=16

12-120% x = 3x-5% x = 5.5 (1 + 25%) x = 7.5 X-30% x = 91.4% x + 6% x = 29.4 x + 25% x = 8.75

The conversion method is to remove the percent sign and move the decimal point forward two places. For example, 60%: remove the percent sign is 60 (60.), and the decimal point moves forward two places to become 0.60; for another example, 5%: remove the percent sign is 5 (5.), and the decimal point moves forward two places to become 0.05.4, 3 = 3 / 4 = 0.75

Solution equation: 12 − x = 1x − 2-6 − x3x2 − 12

The deformation of the equation is: - 1 x − 2 = 1 x − 2-6 − X3 (x − 2) (x + 2), both sides of the equation are multiplied by 3 (X-2) (x + 2) to get: - 3 (x + 2) = 3 (x + 2) - (6-x), the solution is: x = - 67, test: substitute x = - 67 into 3 (X-2) (x + 2) ≠ 0, the solution of the original equation is x = - 67

X + 9 / 2 = 12 two equations 2x-2 / 3x = 1 / 2

(1)x+9/2=12
x=12-9/2
=24/2-9/2
=(24-9)/2
=15/2
(2)2x-2/3x=1/2
6/3x-2/3x=1/2
(6-2)/3x=1/2
4/3x=1/2
x=1/2*3/4=3/8

Given that the solution of equation 3x + 12 = 0 is also the solution of equation x + 3|a | = - 1, then a=______ ．

∵ 3x + 12 = 0, ∵ x = - 4, substitute x = - 4 into the equation x + 3 | a | = - 1 to get: - 4 + 3 | a | = - 1, the solution is: | a | = 1, | a = ± 1