9th Grade Math Problem Cross Multiplication

x²+ax+b=（x+c）（x+d）

where c+d=a

The cross multiplication of cd=b quadratic terms with coefficients has been removed from junior high school, so I won't talk about it. Hope.

x²+ax+b=0

x cx d

where d+c=acd=b

It is to try to split b to a value that can be equal to a.

Get (x+c)(x+d)=0 for example:

x²-3x+2=0

x -1x -2

x+(-2x)=-3x

Get (x-1)(x-2)=0

x²+2√2x+2

x √2x √2

2x+√2x=2√2x

Get (x+ 2)(x+ 2)=0

1.The cross multiplication method mainly solves the factorization problem of the quadratic integer of the integer coefficient (the quadratic term coefficient is an integer). Such as:

The inverse of 3x-2)*(2x+5)=6xsquared + 11x-10 is the cross multiplication.

Principle: First, factor the coefficient of the quadratic term of x to write all the factors, and then decompose the constant term to write all the factors.

Then put the two factors of the quadratic term up and down in a column, and in the same way, the two factors of the constant term are also arranged up and down in a column, as follows.

2 rows and 2 columns of squares, 3 -2 or 3 2 or 3 5 or 3 -5 and so on, and then add the product of the number of squares relative to the vertices 2 5 2 -5 2 -2 2 2 If the resulting sum is exactly equal to the coefficient of the primary term, for example, the first group satisfies the condition, and the last is factored horizontally, the factorization formula 6x2+11x-10=(3x-2)*(2x+5) can be obtained

1.The result of decomposition a-a-12 is (b).

a.（a-3）(a+4) b.(a+3)（a-4）c.(a-6)(a+2) d.(a+6)(a-2)2.The result of decomposing x +2x-8 is (a).

a.（x+4）(x-2)b.(x-4)(x+2)c.(x+4)(x+2) d.(x-4)(x-2)3.Decompose m - (1 6) m - 1 6 (c).

a.（m-1/6）（m+1）b.(m+1/6)（m-1）c.（m-1/2）（m+1/3）d.（m+1/2）（m-1/3

1.The result of decomposition a-a-12 is (b).

2.The result of decomposing x +2x-8 is (a).

3.Decompose m - (1 6) m - 1 6 (c).

2x²+xy-y²

2x-y) (x+y)

The problem is that 2 is divided into = 1 2, and you write it as 2 (Tulu-1).

Because it should be 2 1

The original formula is decomposed into (2x-y) (x+y), you are multiplying the cross correctly, and the column formula is wrong.

For ax 2+bx+c, decompose a into the product of m, n two numbers, and c into the product of p, q, and then sell the unfilial piety column into the following formula: mp

nqpn+mqIf pn+mq=b, then ax 2+bx+c=(mx+p)(nx+q).

If pn+mq ≠ b, then decompose a,c into the product of other numbers, and the formulas listed on the upper surface are cross-multiplied to obtain pn+mq, hence the name "multiplication of ten manuscript characters".

The multiplication of the intersections is equal to the 2 coefficients.