Factorization method: m (X-Y) (X-Y) - x + y

Factorization method: m (X-Y) (X-Y) - x + y

Using the method of extracting common factor
m(x-y)(x-y)-x+y
=m(x-y)(x+y)-(x-y)
=(x-y)(mx+my-1)

(X-2) & # - 4 = 0 i know how to do this, but the teacher said to use factorization,

(x-2）²-4=0
(x-2)²-2²=0
(x-2+2)(x-2-2)=0
x(x-4)=0
X = 0 or x = 4

In the triangle ABC, a = 4, B = 6, C = 120 degrees, find Sina

cosC = (a² + b² - c²)/2ab
-1/2 = (4² + 6² - c²)/(2 × 4 × 6)
c = 2√19
a/sinA = c/sinC
4/sinA = 2√19/(√3/2)
sinA = √57/19

A number a divided by 2007, the remainder is 918, a divided by 223, what is the remainder

Because 2007 △ 223 = 9, there is no remainder, so the number divisible by 2007 can be divisible by 223
So divide the remainder 918 by 223
918 ÷ 223 = 4,26
So the remainder is 26

CD is the diameter of the circle O, AB is the chord, and CD is perpendicular to AB, m, CM = 3cm, DM = 1cm, find the length of the chord ab

Because CD is the diameter of circle O, CD is perpendicular to chord AB and m, so am = BM = AB / 2 (vertical diameter theorem), and because am * BM = cm * DM (intersecting chord theorem), so am ^ 2 = cm * DM = 3 * 1

21.3.14 + 62.3.14 + 17.314 = factorization

21·3.14＋62·3.14＋17·3.14= 3.14×（21+62+17）=3.14×100=314

As shown in the figure, it is known that in △ ABC, BD and CE are bisectors of ∠ B and ∠ C, respectively, ∠ abd = 20 ° and ∠ BDC = 80 °. Calculate the degree of ∠ AEC

153 degrees 19 minutes 42 seconds + 26 degrees 40 minutes 28 seconds = 90 degrees 15 minutes 16 seconds X5 = 90 degrees 3 seconds - 57 degrees 21 minutes 44 seconds=

153 degrees 19 minutes 42 seconds + 26 degrees 40 minutes 28 seconds = 180 degrees 10 seconds 90 degrees 15 minutes 16 seconds X5 = 451 degrees 16 minutes 20 seconds 90 degrees 3 seconds - 57 degrees 21 minutes 44 seconds = 32 degrees 38 minutes 19 seconds

Matrix and determinant problems
If | a | = 0, we prove that | a * | = 0 (where a * is the adjoint matrix of a)

First of all, anyway
AA * = | a | ^ n * I is constant
So because | a | = 0, so AA * = 0
If | a * | is not 0, then a * is reversible. The two ends of the above formula are right multiplied by the inverse of a * to get a = 0, so a * = 0 is contradictory to | a * | is not 0

1288 divided by 28 + 52 times 36
2 17 / 1 * 15 - (5 23 / 21 + 5 17 / 15) important process

1288 divided by 28 + 52 times 36
=46*28/28+(50+2)*36
=46+72+1800
=118+1800
=1918
17/1*15-（5 23/21+5 17/15）
=17/15-(10+23/21+17/15)
=-10-23/21
=-11 and 2 / 21