In elementary school, solving equations is based on the relationship between known numbers and obtained numbers in four operations. We can solve the equation in the following three ways.

First, directly according to the relationship between the known number and the obtained number in the four operations, find the value of the unknown.

For example: 3.6÷x=0.9. This is the division formula, and X is the divisor, which means that the quotient of X divided by 3.6 is 0.9. According to the relationship that divisor equals dividend divided by quotient in division, find the value of x.

Solving equation: 3.6÷x=0.9

Solution: x=3.6÷0.9

x=4

Second, regard the term containing the unknown x as a number and gradually find the value of the unknown.

For example: 2x-6= 14. The term (2x) containing an unknown number is regarded as a number. So 6 is subtraction, 2x is minuend, and 14 is difference. Find out how much 2x equals first, and then find out the value of x further.

Solving equation: 2x-6= 14

Solution: 2x= 14+6

2x=20

x = 20 \2

x= 10

Thirdly, through calculation, the original equation is simplified first, and then the solution of the equation is solved step by step.

For example: 3x-2.5x4 = 5; Calculate 2.5×4 first, and then find the unknown value according to the previous method.

Solving equation: 3x-2.5×4=5

Solution: 3x- 10=5

3x=5+ 10

3x= 15

x= 15÷3

x=5

Another example is: 4.5x+5.5x+3 = 30; Calculate 4.5x+5.5x first, and then find the unknown value according to the previous method.

Solving equation: 4.5x+5.5x+3=30.

Solution: (4.5+5.5)x+3=30.

10x+3=30

10x=30-3

10x=27

x = 27 \ 10

x=2.7

Exercise:

Solve the following equation.

1.2-x = 0.4 2.5x = 63x+5 = 20 6x- 14 = 10

7x-2x = 5(8+x)×8 = 120 5.4-3x = 2×2. 1 5x-2x-7 = 14

How to solve the equation

The steps to solve the equation (1) are as follows: firstly, remove the brackets (2) move the term containing the unknown to the left, and move the constant term to the right (3) merge the similar terms; deform the equation into a monomial (4) divide both sides of the equation by the coefficient of the unknown at the same time to get the value of the unknown. For example: 3+x= 18 solution: x = 18-3 x = 15 ∴ solution: 4x+158-2x =1924x-2x+/kloc. .28 (only take two decimal places after π) To solve this problem, we must first know how much π equals, π=3. 14 15926535, only take 3. 14, and the solution is 3.14r = 6.28/3. Some formulas have an X on the right, which can be simply calculated in a different position. The root formula of the unary cubic equation can't be worked out by ordinary deductive thinking. The standard unary cubic equation of AX 3+BX 2+CX+D+0 can only be formalized into a special type of X 3+PX+Q = 0 by using a matching method similar to the root formula of the unary quadratic equation. The solution of the solution formula of the univariate cubic equation can only be obtained by inductive thinking, that is, the form of the root formula of the univariate cubic equation is summarized according to the form of the root formula of the univariate quadratic equation and the special higher order equation. The formula for finding the root of a univariate cubic equation in the form of x 3+px+q = 0 should be X = A (1/3)+B (1/3), which is the sum of two exponents. Summarize the form of the root formula of the unary cubic equation, and then find the content of the square, that is, use P and Q to represent A and B. The method is as follows: (1) cubic X = A (1/3)+B (1/3) and get (2) x 3 = (at the same time. 3), so (2) can be changed into x 3 = (a+b)+3 (ab) (1/3) x, (4) x 3-3 (ab) (1/3) x-(a+) is simplified to (6) a. The roots of the univariate cubic equation are actually formulated into the root formula of the univariate quadratic equation, because A and B can be regarded as two roots of the univariate quadratic equation, and (6) is in the form of ay 2+by+c =. Y 1*y2=c/a (9) Compare (6) and (8), A = Y 1, B = Y2, Q = B/A, -(p/3) 3 = c/a (10). y 1 =-(b/2a)-(b/2a)2-(c/a))( 1/2)y2 =-(b/2a)+((b/2a)2-(c/a))。 ......

How to solve the equation? Use a calculator

Refer to the Chinese description of TI84 Plus.

wenku.baidu/...=5 1NaN

How come? Proportion of solving equation

Solution: Make it a root.

126:x=9:5

9x= 126*5

x=630/9

X=70

8+x equals 20, how to solve the equation,

8+x=20

Both sides of the equation at the same time -8

x=20-8

x= 12