Mathematics! How do you solve the square of X 10X 21 0? To detail the process, thanks

Multiply with crossesSplit 21 into +3 and +7 to get (x+3)(x+7)=0 to get x -3 or x -7

Methods for solving equations:

1. Estimation method: an introductory method when you just learn to solve equations. The solution of the equation is directly estimated and then verified by substitute for the original equation.

2. Apply the properties of the equation to solve the equation.

3. Merge similar items.

Deform the equation into a monomial.

4. Move Terms: Move items with unknown numbers to the left, constant items.

Move to the right. For example: 3+x=18

Solution: x=18-3

x=15

There are several ways to do this.

Factorization. x²+10x+21=0

x²+(3+7)x+3×7=0

x+3)(x+7)=0

x+3=0 or x+7=0

The solution is x1=-3 and x2=-7

Formula method. x²+10x+21=0

a=1,b=10,c=21

b²-4ac=16>0

It is obtained by the root finding formula.

x=(-b root number b -4ac) 2a=(-10 4) 2 solution gives x1=-3, x2=-7

Matching method. x²+10x+21=0

x²+10x=-21

x²+10x+5²=-21+25

x+5）²=4

x+5=±2

x=-5±2

The solution is x1=-3 and x2=-7

Multiply with crosses

Split 21 into +3 and +7 to get (x+3)(x+7)=0

Solve x -3 or x -7

Splitting the constant 21 into 3 and 7 gives (x+3)(x+7)=0

Solution: -3 or -7

Factoring yields (x+3)(x+7)=0, and solves for x=-3 or x=-7

The three methods tell you that this kind of question is solved.

Solution: 2 10 10 10 21 = 0 factorization yields ( 10 3) ( 10 7) = 0 1=-3, 2 = -7

Summary. Finding the Root Formula to Solve a Quadratic Equation, x=【-b (b -4AC)】 The general form of solving a quadratic equation by the collocation method, ax +bx+c=0, the formula for finding the root can be obtained x=[-b (b -4AC)] First observe whether the solved equation is a general form of a quadratic equation, if it is not changed to a general form by shifting terms, 3Find the value of the coefficient and bring it into the root finding formula, you can get the value of x, math!

How to solve x squared + 10x + 21 = 0? To detail the process, thanks

Hello Cong Qin, dear decompose the coefficient of x -10 into Zheng Qi-3 and -7, so that 21 is the product of -3 and -7, so the solution is -3 and -7

Is it possible to use the square of b minus 4ac?

Explain. Thank you.

Finish. Finding the Root Formula to Solve a Quadratic Equation, x=[Difference-b (b -4AC)] By solving the general form of a quadratic equation by the matching method, ax +bx+c=0, the formula for finding the root can be obtained x=[-b (b -4AC)] False World Reputation First observe whether the solved equation is a general form of a one-dimensional quadratic equation, if it does not change to a general form by shifting terms, 3Find the value of the coefficient and bring it into the root formula, you can get the value of x, and find the root formula to solve the unary quadratic equation, x=[-b (b -4ac)] The general form of the manuscript of the unary quadratic equation is solved by the matching method, silver ax +bx+c=0, and the root finding formula x=[-b (b -4ac)] First observe whether the solved equation is a general form of a quadratic equation, if it is not changed to a general form by shifting terms, 3

Find the value of the coefficient and bring it into the root finding formula when the key swim to get the value of x.

Multiplication with a cross is faster.

The multiplication and addition of the opposite numbers of the two roots is the sum of the coefficients of the primary term, and the multiplication of the two numbers is the constant term.

3x7=21 3x1+7x1=10

So it has two roots, one is -7 and one is -3

Multiplication with a cross is faster.

The multiplication and addition of the opposite number of the two roots is a sum of the coefficients of the term.

The multiplication of two numbers is the term of the beam resistance constant.

3x7=21

3x1+7x1=10

So it's two roots.

One is -7 and one is -3

We can see from the middle 10 that the other square term is (10 2) 2, so move 21 to the right and add 25 to both sides.