List equations based on the meaning of the question How to list equations based on the meaning of th

1) There is a rectangle with an area of 54 square meters, cut one side of it short by 5 meters, and the other side cut short by 2 meters, which happens to be a square, what is the side length of this square?

Let the sides of the square be x meters long.

x+5)*(x+2)=54

x^2+7x-44=0

x-4)(x+11)=0

x=4 x=-11 (unsuitable, discard).

The side length of this square is 4 meters.

2): Three consecutive integers are multiplied by two, in summing, the result is 242, what is this phone?

Let these three consecutive integers be x-1, x, x+1

x-1)x+x(x+1)+(x-1)(x+1)=2423x^2=243

x^2=81

x= 9 The three integers are either -10, -9, -83) One day ago, a drunk man entered the house with a bamboo pole, and he couldn't take it horizontally and vertically, 4 feet wider than the door frame horizontally, and 2 feet higher than the door frame vertically, and another drunk told him to take the rod diagonally along the two opposite corners of the door, and this drunk man tried it, no more, no less, just went in, do you know how long the bamboo pole is?

Set up bamboo poles x meters long.

x-4)^2+(x-2)^2=x^2

x^2-12x+20=0

x-10)(x-2)=0

x=10 x=2 (unsuitable, discard).

This bamboo pole is 10 feet long.

1 Solution: Let the length of the rectangle be x, then the width is 54 x columns The equation is x-5=54 x-2

2 Solution: Let the middle number be x, then the other two numbers are x-1, and the x+1 column equation is (x-1)x+x(x +1)+(x-1)(x+1)=242

3 Solution: Let the bamboo pole be long x ruler, and the column equation is xx=(x-2)(x-2)+(x-4)(x-4).

Solving problem problems is an important aspect of connecting middle school mathematics with practice. The specific steps are:

Review: Understand the meaning of the question. Find out what the known quantities are in the problem, what the unknown quantities are, and what is the equality relationship between the questions given and the ones involved.

Set the element (unknown): find the equivalence relationship: find the equality relationship that can represent the meaning of the question;

Direct Unknowns: Set the unknowns and list the equations: After setting the unknowns, the relevant equations containing letters are expressed, and then the equations are listed by using the found equiquantitative relations;

Indirect unknowns (often both).

In general, the more unknowns, the easier the equation is to list, but the harder it is to solve.

Represent the quantities of relevance in an algebraic formula with unknowns.

Look for equality relations (some given by the problem and some by the equivalence relations involved in the problem), column equations. In general, the number of unknowns is the same as the number of equations.

Solving equations and testing. Answer.

1. Let this number be x, (x-(-1))*2=8, x=32, let the first number be x, x+x+1+x+2=147, x=483, and after x, 13+x=(39+x) 2

4. Let the length of the candle be y, and B will be half of A after x hours, (y-y 8*x)*1 2=(y-y 6) in the question y can be approximated.

5 As the question, knowing that there are 12 pentagons, then, according to the number of hexagons connected by the pentagon and the number of other pentagons separated by each other and the number of pentagons connected by the hexagons, the calculation formula is obtained: 5*12*2 6=20, that is, 12 regular pentagons and 20 regular hexagons.

1 All 1 (x-2)/3=x-3

2.What does it mean to turn over?

3.Let these three numbers be x-1 , x , x+1x-1 + x+ x+1=33

3x+30=225 65*2=130

Solution: Bonding Na3x = 225-30 130 + 30 = 1603x = 195

x =195/3

x = 65 A: There are no 65 bags of flour and 160 bags of rice. Bent silver.

Let's meet after X amount of time. 6x+

1 3 (Brother Ming x-2) = x-3

Want to turn over? It's the opposite. 2/1？Direct 2 times or 1 2 ... 40%x=-1/2x-1/2

x-1）+x+（x+1）=33