tim x biet : (2x+3)^2x - 2*(2x+3)*(2x-5)+(2x-5)^2=x^2+6x+64
tim x,(2x+3)^2-2(2x+3)(2x-5)+(X+5)^2=x^2+6x+64
tim x biet (3-căn 2x)*(2-3 căn 2x)=6x-5
\(\left(3-\sqrt{2x}\right)\left(2-3\sqrt{2x}\right)=6x-5\)ĐK : x>= 0
\(\Leftrightarrow6-9\sqrt{2x}-2\sqrt{2x}+6x=6x-5\)
\(\Leftrightarrow-11\sqrt{2x}+6x+6=6x-5\Leftrightarrow-11\sqrt{2x}=-11\)
\(\Leftrightarrow\sqrt{2x}=1\Leftrightarrow2x=1\Leftrightarrow x=\dfrac{1}{2}\left(tm\right)\)
Tim x,
a,2x^4-6x^3+x^2+6x-3=0
b,x^3-9x^2+26x+24=0
c, P= 2x^4 - 4x^3 + 6x^2 - 4x + 5 biet rang x^2 - x=7
a)\(2x^4-6x^3+x^2+6x-3=0\)
\(\Leftrightarrow2x^4-6x^3+3x^2-2x^2+6x-3=0\)
\(\Leftrightarrow x^2\left(2x^2-6x+3\right)-\left(2x^2-6x+3\right)=0\)
\(\Leftrightarrow\left(x^2-1\right)\left(2x^2-6x+3\right)=0\)
\(\Leftrightarrow\left(x-1\right)\left(x+1\right)\left(2x^2-6x+3\right)=0\)
\(\Leftrightarrow\left[\begin{array}{nghiempt}x-1=0\\x+1=0\\2x^2-6x+3=0\end{array}\right.\)\(\Leftrightarrow\left[\begin{array}{nghiempt}x=1\\x=-1\\\Delta_{2x^2-6x+3}=\left(-6\right)^2-4\left(2.3\right)=12\end{array}\right.\)
\(\Leftrightarrow\left[\begin{array}{nghiempt}x=1\\x=-1\\x_{1,2}=\frac{6\pm\sqrt{12}}{4}\end{array}\right.\)
b)\(x^3+9x^2+26x+24=0\)
\(\Leftrightarrow x^3+5x^2+6x+4x^2+20x+24=0\)
\(\Leftrightarrow x\left(x^2+5x+6\right)+4\left(x^2+5x+6\right)=0\)
\(\Leftrightarrow\left(x^2+5x+6\right)\left(x+4\right)=0\)
\(\Leftrightarrow\left(x+2\right)\left(x+3\right)\left(x+4\right)=0\)
\(\Leftrightarrow\left[\begin{array}{nghiempt}x+2=0\\x+3=0\\x+4=0\end{array}\right.\)\(\Leftrightarrow\left[\begin{array}{nghiempt}x=-2\\x=-3\\x=-4\end{array}\right.\)
Tìm x , biết :
a) (3x -1)(2x+7) -(x+1)(6x-5) =16
b) (2x +3)2-2(2x+3)(2x-5)+(2x-5)2= x2+6x+64
c) (x4+2x3+10x-25): (x2+5)=3
a) \(\left(3x-1\right)\left(2x+7\right)-\left(x+1\right)\left(6x-5\right)=16\)
\(\Leftrightarrow\left(6x^2+21x-2x-7\right)-\left(6x^2-5x+6x-5\right)-16=0\)
\(\Leftrightarrow6x^2+21x-2x-7-6x^2+5x-6x+5-16=0\)
\(\Leftrightarrow18x-18=0\)
\(\Leftrightarrow18x=18\)
\(\Leftrightarrow x=18:18\)
\(\Leftrightarrow x=1\)
Vậy \(x=1\)
b) \(\left(2x+3\right)^2-2\left(2x+3\right)\left(2x-5\right)+\left(2x-5\right)^2=x^2+6x+64\)
\(\Leftrightarrow\left[\left(2x+3\right)-\left(2x-5\right)\right]^2-\left(x^2+6x+64\right)=0\)
\(\Leftrightarrow\left(2x+3-2x+5\right)^2-x^2-6x-64=0\)
\(\Leftrightarrow8^2-x^2-6x-64=0\)
\(\Leftrightarrow64-x^2-6x-64=0\)
\(\Leftrightarrow-x^2-6x=0\)
\(\Leftrightarrow x\left(-x-6\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\-x-6=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\-x=6\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=-6\end{matrix}\right.\)
Vậy \(x=0\) hoặc \(x=-6\)
a) \(\left(3x-1\right)\left(2x+7\right)-\left(x+1\right)\left(6x-5\right)=16\)
\(\Leftrightarrow\left(6x^2+21x-2x-7\right)-\left(6x^2-5x+6x-5\right)-16=0\)
\(\Leftrightarrow6x^2+21x-2x-7-6x^2+5x-6x+5-16=0\)
\(\Leftrightarrow18x-18=0\)
\(\Leftrightarrow18x=18\)
\(\Leftrightarrow x=18:18\)
\(\Leftrightarrow x=1\)
Vậy \(x=1\)
b, \(\left(2x+3\right)^2-2\left(2x+3\right)\left(2x-5\right)+\left(2x- 5\right)^2=x^2+6x+64\)
\(\Leftrightarrow\left[\left(2x+3\right)-\left(2x-5\right)\right]^2- \left(x^2+6x+64\right)=0\)
\(\Leftrightarrow\left(2x+3-2x+5\right)^2-x^2-6x-64=0\)
\(\Leftrightarrow8^2-x^2-6x-64=0\)
\(\Leftrightarrow64-x^2-6x-64=0\)
\(\Leftrightarrow-x^2-6x=0\)
\(\Leftrightarrow x\left(-x-6\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\-x-6=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\-x=6\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=-6\end{matrix}\right.\)
Vậy \(x=0\) hoặc \(x=6\)
a) (3x−1)(2x+7)−(x+1)(6x−5)=16(3x−1)(2x+7)−(x+1)(6x−5)=16
⇔(6x2+21x−2x−7)−(6x2−5x+6x−5)−16=0⇔(6x2+21x−2x−7)−(6x2−5x+6x−5)−16=0
⇔6x2+21x−2x−7−6x2+5x−6x+5−16=0⇔6x2+21x−2x−7−6x2+5x−6x+5−16=0
⇔18x−18=0⇔18x−18=0
⇔18x=18⇔18x=18
⇔x=18:18⇔x=18:18
⇔x=1⇔x=1
Vậy x=1x=1
b) (2x+3)2−2(2x+3)(2x−5)+(2x−5)2=x2+6x+64(2x+3)2−2(2x+3)(2x−5)+(2x−5)2=x2+6x+64
⇔[(2x+3)−(2x−5)]2−(x2+6x+64)=0⇔[(2x+3)−(2x−5)]2−(x2+6x+64)=0
⇔(2x+3−2x+5)2−x2−6x−64=0⇔(2x+3−2x+5)2−x2−6x−64=0
⇔82−x2−6x−64=0⇔82−x2−6x−64=0
⇔64−x2−6x−64=0⇔64−x2−6x−64=0
⇔−x2−6x=0⇔−x2−6x=0
⇔x(−x−6)=0⇔x(−x−6)=0
⇔[x=0−x−6=0⇔[x=0−x−6=0
⇔[x=0−x=6⇔[x=0−x=6
⇔[x=0x=−6⇔[x=0x=−6
Vậy x=0x=0 hoặc x=−6
\(\left(2x+3\right)^2-2\left(2x^2+3\right)\left(2x-5\right)+\left(2x-5\right)^2=x^2+6x+64\)
(2x+3)^2-2(2x+3)(2x-5)+(2x-5)^2=x^2+6x+64
=>x^2+6x+64=(2x+3-2x+5)^2
=>x^2+6x+64=64
=>x(x+6)=0
=>x=0 hoặc x=-6
Tìm x: a) (3x-1)(2x+7) - (x+1)(6x-5) = 16
b) (2x+3)2 - 2(2x+3)(2x-5) + (2x-5)2 = x2 + 6x + 64
I) THỰC HIỆN PHÉP TÍNH a) 2x(x^2-4y) b)3x^2(x+3y) c) -1/2x^2(x-3) d) (x+6)(2x-7)+x e) (x-5)(2x+3)+x II phân tích đa thức thành nhân tử a) 6x^2+3xy b) 8x^2-10xy c) 3x(x-1)-y(1-x) d) x^2-2xy+y^2-64 e) 2x^2+3x-5 f) 16x-5x^2-3 g) x^2-5x-6 IIITÌM X BIẾT a)2x+1=0 b) -3x-5=0 c) -6x+7=0 d)(x+6)(2x+1)=0 e)2x^2+7x+3=0 f) (2x-3)(2x+1)=0 g) 2x(x-5)-x(3+2x)=26 h) 5x(x-1)=x-1 IV TÌM GTNN,GTLN. a) tìm giá trị nhỏ nhất x^2-6x+10 2x^2-6x b) tìm giá trị lớn nhất 4x-x^2-5 4x-x^2+3
Giải như sau.
(1)+(2)⇔x2−2x+1+√x2−2x+5=y2+√y2+4⇔(x2−2x+5)+√x2−2x+5=y2+4+√y2+4⇔√y2+4=√x2−2x+5⇒x=3y(1)+(2)⇔x2−2x+1+x2−2x+5=y2+y2+4⇔(x2−2x+5)+x2−2x+5=y2+4+y2+4⇔y2+4=x2−2x+5⇒x=3y
⇔√y2+4=√x2−2x+5⇔y2+4=x2−2x+5, chỗ này do hàm số f(x)=t2+tf(x)=t2+t đồng biến ∀t≥0∀t≥0
Công việc còn lại là của bạn !
\(\left(x+6\right)\left(2x+1\right)=0\)
<=> \(\orbr{\begin{cases}x+6=0\\2x+1=0\end{cases}}\)
<=> \(\orbr{\begin{cases}x=-6\\x=-\frac{1}{2}\end{cases}}\)
Vậy....
hk tốt
^^
tim x
-2x(6x-2)+3x(4x-7)=8
(7x-2)(2x+3)-(3x-5)(4x+6)=2x2-5
+(-2x+3)-6x(3x-4)=-22x2+7x
⇔(2 x ) 2+2.2 x .1+1 2=0 ... c ,(3 x −4) 2−14(3 x −4)(6+3 x )+49(3 x +6)=16 ... ⇔9 x 2−24 x +16−126 x 2−252 x +168 x +336+147 x +294=16.
https://olm.vn/hoi-dap/detail/192758180810.html
\(-2x\left(6x-2\right)+3x\left(4x-7\right)=8\)
<=> \(-12x^2+4x+12x^2-21x=8\)
<=> \(-17x=8\)
<=> \(x=-\frac{8}{17}\)
\(\left(7x-2\right)\left(2x+3\right)-\left(3x-5\right)\left(4x+6\right)=2x^2-5\)
<=> \(14x^2+17x-6-12x^2+2x+30=2x^2-5\)
<=> \(14x^2+17x-6-12x^2+2x+30-2x^2+5=0\)
<=> \(19x+29=0\)
<=> \(19x=-29\)
<=> \(x=-\frac{29}{19}\)
Ý cuối mình k biết -22x2 là -22.2 hay -22x2 nữa :)
giải các phương trình sau
\(\left(3x-1\right)\left(2x+7\right)-\left(x+1\right)\left(6x-5\right)=\)16
\(\left(2x+3\right)^2-2\left(2x+3\right)\left(2x-5\right)+\left(2x-5\right)^2=x^2+6x+64\)
\(\left(x^4+2x^3+10x-25\right):\left(x^2+5\right)=3\)