\(=5x^4-15x^3+10x^2\)

Vậy không đáp án nào đúng

`1,(4x^3+3x^3):x^3+(15x^2+6x):(-3x)=0`

`<=> 4 + 3 + (-5x) + (-2)=0`

`<=> -5x+5=0`

`<=>-5x=-5`

`<=>x=1`

`2,(25x^2-10x):5x +3(x-2)=4`

`<=> 5x - 2 + 3x-6=4`

`<=> 8x -8=4`

`<=> 8x=12`

`<=>x=12/8`

`<=>x=3/2`

`3,(3x+1)^2-(2x+1/2)^2=0`

`<=> [(3x+1)-(2x+1/2)][(3x+1)+(2x+1/2)]=0`

`<=>( 3x+1-2x-1/2)(3x+1+2x+1/2)=0`

`<=>( x+1/2) (5x+3/2)=0`

`@ TH1`

`x+1/2=0`

`<=>x=0-1/2`

`<=>x=-1/2`

` @TH2`

`5x+3/2=0`

`<=> 5x=-3/2`

`<=>x=-3/2 : 5`

`<=>x=-15/2`

`4, x^2+8x+16=0`

`<=>(x+4)^2=0`

`<=>x+4=0`

`<=>x=-4`

`5, 25-10x+x^2=0`

`<=> (5-x)^2=0`

`<=>5-x=0`

`<=>x=5`

`1)<=> -4x-3 + 5x+ 2 =0`

`<=> 5x-4x = -2+3`

`<=> x =1`

`2)<=> -5x +2-3x+6 =4`

`<=> -5x-3x = 4-6-2`

`<=> -8x=-4`

`<=> x=1/2`

`3) <=> -7x^2 +2 +7x^2 +14x =8`

`<=> 14x +2 =8`

`<=> 14x = 6`

`<=> x=3/7`

\(6x-15x^2\Leftrightarrow3x\left(2-5x\right)\)

\(6x-15x^2=3x\left(2-5x\right)\)

15 x 2 = 30.

bang 30

\(15x2=30\)

30 k nhé

15x2=30

15*2=30

15x2

=15+15

=   30.

K nhé bạn Hiên Lovely, tớ cho cậu rồi.

15x2=30

15x2=30

15x2=30

Số cần tìm là : 

15 x 2 = 30

Đáp số : 30

= 30 nha bạn Chi

`-15x^2+170x-55=0`

`<=>15x^2-170x+55=0`

`<=>(15x^2-165x)-(5x-55)=0`

`<=>15x(x-11)-5(x-11)=0`

`<=>(15x-5)(x-110)=0`

`<=>` \(\left[{}\begin{matrix}x=\dfrac{1}{3}\\x=11\end{matrix}\right.\)

\(-15x^2+170x-55=0\)

\(\Delta=170^2-4.\left(-15\right).\left(-55\right)\)

\(=28900-3300\)

\(=25600>0\Rightarrow\sqrt{\Delta}=160\)

\(\Rightarrow\)Phương trình có 2 nghiệm phân biệt:

\(x_1=\dfrac{-170-160}{2.\left(-15\right)}=11\)                         \(x_2=\dfrac{-170+160}{2.\left(-15\right)}=\dfrac{1}{3}\)

Vậy phương trình có 2 nghiệm là x1=11;x2=\(\dfrac{1}{3}\)

-Chúc bạn học tốt-

TK

\(-15x^2+170x-55=0\)

\(15x^2-170x+55\)

\(15x^2-165x-5x-55=0\)

\(\left(15x^2-165x\right)-\left(5x-55\right)=0\)

\(15x\left(x-11\right)-5\left(x-11\right)\)

\(\left(x-11\right)\left(15x-5\right)=0\)

\(\left[{}\begin{matrix}x=11\\x=\dfrac{1}{3}\end{matrix}\right.\)

Vậy \(x\in\left\{\dfrac{1}{3};11\right\}\)

\(=5+x-\dfrac{1}{3}x^2\)