Đáp án:

Giải thích các bước giải:

13) −8𝑥²+5𝑥+3

=−1(8𝑥²−5𝑥−3)

=−1(8𝑥²+3𝑥−8𝑥−3)

=−1[𝑥(8𝑥+3)−1(8𝑥+3)]

=−1(𝑥−1)(8𝑥+3)

14) 8𝑥²−10𝑥−3

=8𝑥²+2𝑥−12𝑥−3

=2𝑥(4𝑥+1)−3(4𝑥+1)

=(2𝑥−3)(4𝑥+1)

15) 8𝑥²+10𝑥−3

=8𝑥²+12𝑥−2𝑥−3

=4𝑥(2𝑥+3)−1(2𝑥+3)

=(4𝑥−1)(2𝑥+3)

16) −8𝑥²+23𝑥+3

=−1(8𝑥²−23𝑥−3)

=−1(8𝑥²+𝑥−24𝑥−3)

=−1[𝑥(8𝑥+1)−3(8𝑥+1)]

=−1(𝑥−3)(8𝑥+1)

17) 8𝑥²−23𝑥−3

=8𝑥²+𝑥−24𝑥−3

=𝑥(8𝑥+1)−3(8𝑥+1)

=(𝑥−3)(8𝑥+1)

18) 10𝑥²−11𝑥−6

=10𝑥²+4𝑥−15𝑥−6

=2𝑥(5𝑥+2)−3(5𝑥+2)

=(2𝑥−3)(5𝑥+2)

19) −10𝑥²+11𝑥+6

=−1(10𝑥²−11𝑥−6)

=−1(10𝑥²+4𝑥−15𝑥−6)

=−1[2𝑥(5𝑥+2)−3(5𝑥+2)]

=−1(2𝑥-3)(5𝑥+2)

21) −10𝑥²+4𝑥+6

=−2(5𝑥²−2𝑥−3)

=−2(5𝑥²+3𝑥−5𝑥−3)

=−2[𝑥(5𝑥+3)−1(5𝑥+3)]

=−2(𝑥−1)(5𝑥+3)

22) 10𝑥²+7𝑥−6

=10𝑥²+12𝑥−5𝑥−6

=2𝑥(5𝑥+6)−1(5𝑥+6)

=(2𝑥−1)(5𝑥+6)

24) 10𝑥²+17𝑥−6

=10𝑥²+20𝑥−3𝑥−6

=10𝑥(𝑥+2)−3(𝑥+2)

=(10𝑥−3)(𝑥+2)

26) −10𝑥²+28𝑥+6

=−2(5𝑥²−14𝑥−3)

=−2(5𝑥²+𝑥−15𝑥−3)

=−2[𝑥(5𝑥+1)−3(5𝑥+1)]

=−2(𝑥−3)(5𝑥+1)

27) 10𝑥²−28𝑥−6

=2(5𝑥²−14𝑥−3)

=2(5𝑥²+𝑥−15𝑥−3)

=2[𝑥(5𝑥+1)−3(5𝑥+1)]

=2(𝑥−3)(5𝑥+1)

28) 10𝑥²−7𝑥−12

=10𝑥²+8𝑥−15𝑥−12

=2𝑥(5𝑥+4)−3(5𝑥+4)

=(2𝑥−3)(5𝑥+4)

29) −10𝑥²+7𝑥+12

=−1(10𝑥²−7𝑥−12)

=−1(10𝑥²+8𝑥−15𝑥−12)

=−1[2𝑥(5𝑥+4)−3(5𝑥+4)]

=−1(2𝑥−3)(5𝑥+4)

30) 10𝑥²−14𝑥−12

=2(5𝑥²−7𝑥−6)

=2(5𝑥²+3𝑥−10𝑥−6)

=2[𝑥(5𝑥+3)−2(5𝑥+3)]

=2(𝑥−2)(5𝑥+3)

À còn câu 12, 20 và câu 25 nx mà mik vẫn chx nghĩ cách giải chừng nào có r mik tl dười phần bình luận cho bn nha^^

Thông cảm dùm mik nha😘😘

Đáp án + Giải thích các bước giải:

 `1) 3x^2+7x-6`

`=3x^2+9x-2x-6`

`=3x(x+3)-2(x+3)`

`=(3x-2)(x+3)`

_______________________

`2) 3x^2+3x-6`

`=3x^2+6x-3x-6`

`=3x(x+2)-3(x+2)`

`=(3x-3)(x+2)`

`=3(x-1)(x+2)`

________________________

`3)3x^2-3x-6`

`=3x^2-6x+3x-6`

`=3x(x-2)+3(x-2)`

`=(3x+3)(x-2)`

`=3(x+1)(x-2)`

_______________________

`4) 6x^2-13x+6`

`=6x^2-4x-9x+6`

`=2x(3x-2)-3(3x-2)`

`=(2x-3)(3x-2)`

___________________________

`5) 6x^2+13x+6`

`=6x^2+4x+9x+6`

`=2x(3x+3)+3(3x+2)`

`=(2x+3)(3x+2)`

_____________________________

`6) 6x^2 +15x+6`

`=6x^2+12x+3x+6`

`=6x(x+2)+3(x+2)`

`=(6x+3)(x+2)`

`=3(2x+1)(x+2)`

_______________________

`7) 6x^2-15x+6`

`=6x^2-3x-12x+6`

`=3x(2x-1)-6(2x-1)`

`=(3x-6)(2x-1)`

`=3(x-2)(2x-1)`

__________________________

`8) 6x^2+20x+6`

`= 6x^2+18x+2x+6`

`=6x(x+3)+2(x+3)`

`=(6x+2)(x+3)`

`=2(3x+1)(x+3)`

___________________________

`9) 6x^2-20x+6`

`=6x^2-18x-2x+6`

`=6x(x-3)-2(x-3)`

`=(6x-2)(x-3)`

`=2(3x-1)(x-3)`

__________________________

`10) 6x^2+12x+6`

`=6x^2+6x+6x+6`

`=6x(x+1)+6(x+1)`

`=(6x+6)(x+1)`

`=6(x+1)(x+1)=6(x+1)^2`

____________________________

`11) 8x^2-2x-3`

`=8x^2+4x-6x-3`

`=4x(2x+1)-3(2x+1)`

`=(4x-3)(2x+1)`

____________________________

`12) 8x^2 + 2x-3`

`=8x^2-4x+6x-3`

`=4x(2x-1)+3(2x-1)`

`=(4x+3)(2x-1)`

___________________________

`20) 10x^2-4x-6`

`= 10x^2-10x+6x-6`

`=10x(x-1)+6(x-1)`

`=(10x+6)(x-1)`

`=2(5x+3)(x-1)`

___________________________

`25) -10x^2-17x+6`

`= -10x^2-20x+3x+6`

`= -10x(x+2)+3(x+2)`

`=(-10x+3)(x+2)`

`=(3-10x)(x+2)`