Mathematical Equations, 7th grade unary equations

Solution: Remove the denominator, got.

Move the item, got. Merge similar items to obtain.

coefficient to 1, obtained.

x=-593

x+3）/3-x=（x+1）/2+1

Solution: Remove the denominator, got.

2x+6-6x=3x+3+6

Move the item, got. 2x-6x-3x=3+6-6

Merge similar items to obtain.

7x=3 coefficient to 1, obtained.

x= -3/7

General solution:

1.Denominator: multiply by the least common multiple of each denominator on both sides of the equation (the term without the denominator is also multiplied);

2.Remove braces: first go to the small braces, then the middle brackets, and finally the braces; (Remember to change the sign if there is a minus sign outside the parentheses).

3.Shift: Move all terms with unknowns to one side of the equation and all other terms to the other side of the equation; The move item needs to be renumbered.

4.Merge similar terms: Equations are formed in the form ax=b(a≠0);

5.Factor 1: Divide the coefficient a by the unknown on both sides of the equation to get the solution of the equation x=b a

Important ways to do unary equation application problems:

Carefully review the topic (review the topic).

Analyze known and unknown quantities.

Find a suitable equivalence relationship.

Assign an appropriate unknown.

Make a list of reasonable equations (columns).

Solve the equation (problem solving).

Test Write out the answer (answer).

Polynomial 2 (x-2) is 9 greater than polynomial 3 (4x-1), i.e. 2 (x-2) -3 (4x-1) = 9

2x-4-12x+3=9

10x=10

x=-1Therefore, there is no correct answer for question 1.

2. Question A

Solution: Let the speed of the passenger car be 5xm s and the speed of the truck be 3xm s, then the equation is: 18 (5x+3x) = 200 + 280

x=10/3

So the passenger car speed is 5x=50 3(m s).

The speed of the wagon is 3x=10(m s).

Solution: Let the truck speed be x meters per second, 18*(5 3+3)x=200+280

Solution: x=10 m seconds.

A: Passenger cars travel 50 3 meters per second, and trucks travel 10 meters per second.

In fact, this is a matter of encounter, and the distance is the sum of the lengths of the two cars.

Solution: If one is x, then the passenger car is 5x and the train is 3x

18*5x+18*3x=200=280

x=10/3

5x=50/3

3x=10

Solution: If one is x, then the passenger car is 5x and the train is 3x

18*5x+18*3x=200=280

x=10/3

5x=50/3

3x=10