數 學 救 命 !! 五 識 做

1. 3x^2 + 4x
= x(3x + 4)
2. x^2 - x^3y^2 - x^2y^3
= x^2(1 - xy^2 - y^3)
3 . 6x^2 - 9xy + 3x
= 3x(2x - 3y + 1)
4. 5(x+y) - (x+y)
= (x + y)(5 - 1)
= 4(x + y)
5 . 3(3x - 2y) -x (-3x + 2y)
= 3(3x - 2y) + x(3x - 2y)
= (3x - 2y)(3 + x)
6. x(x-y) + (y-x)
= x(x - y) - (x - y)
= (x - y)(x - 1)
7. 8x + 4y + 2x^2 + xy
= 2x^2 + 8x + xy + 4y
= 2x(x + 4) + y(x + 4)
= (x + 4)(2x + y)
8. 9x^2 - 3x - a + 3ax
= 9x^2 - 3x + 3ax - a
= 3x(3x - 1) + a(3x - 1)
= (3x - 1)(3x + a)

1. 3x² + 4x
= x(3x+4)

2. x² - x³y² - x²y³
= x²(1- xy²-y³)
= -x²(y³+xy²-1)

3 . 6x² - 9xy + 3x
= 3x(2x-3y+1)

4. 5(x+y) - (x+y)
= (x+y)(5-1)

5 . 3(3x - 2y) -x (-3x + 2y)
= 3(3x-2y) +x (3x-2y)
= (3x-2y)(3+x)

6. x(x-y) + (y-x)
= x(x-y) – (x-y)
= (x-y)(x-1)

7. 8x + 4y+2x² + xy
= 8x+2x²+4y+xy
= 2x(4+x) +y(4+x)
= (4+x)(2x+y)

8. 9x² - 3x - a + 3ax
= 3x(3x-1) - a(1-3x)
= 3x(3x-1) +a(3x-1)
= (3x-1)(3x+a)