Tìm x biết: a, (x+3).(x-3)+x.(3-x)=0
b, x.(x-3)+x-3=0
Bài 13: Tìm x biết: a) (x-2)(x-3)-D0. b) (x-3)(x-4)-0. c) (x-7)(6-x)=0. d) (x-3)(x-13)=0. The Bài 14: Tìm x biết: a) (12-x)(2-x)=0. b) (x-33)(11-x)=0. c) (21-x)(12-x)=0. d) (50-x)(x-150) =0. Bài 15: Tìm x biết: a) 2x +x = 45. b) 2x +7x = 918. c) 2x+3x 60+5. d) 11x+22x 33.2.
Tìm biết: a) x (x - 6) = 0; b) x (x + 5) = 0; c) (x + 3)(x - 7) = 0; d) (x - 3) ( x 2 + 12) = 0
Tìm x thuộc Z biết: a) x ( x - 2) = 0 b) x ( x + 7 ) = 0 c) ( x + 6) ( x - 4) = 0; d) ( x - 3) ( 2 x 2 + 3) = 0
Tìm x thuộc Z biết: a) x (x - 7) = 0; b) x (x + 11) = 0; c) (x + 8) (x - 12) = 0; d) (x - 3) ( x 2 + 3) = 0;
Tìm x ≥ 0, biết:
a) 2x-7\(\sqrt{x}\)+3=0
b) 3\(\sqrt{x}\)+5 < 6
c) x-3\(\sqrt{x}\) -10 < 0
d) x- 5\(\sqrt{x}\) +6 = 0
e) x+ 5\(\sqrt{x}\) -14 < 0
\(\left(a\right):2x-7\sqrt{x}+3=0\left(x\ge0\right)\\ < =>\left(2x-6\sqrt{x}\right)-\left(\sqrt{x}-3\right)=0\\ < =>2\sqrt{x}\left(\sqrt{x}-3\right)-\left(\sqrt{x}-3\right)=0\\ < =>\left(2\sqrt{x}-1\right)\left(\sqrt{x}-3\right)=0\\ =>\left[{}\begin{matrix}2\sqrt{x}-1=0\\\sqrt{x}-3=0\end{matrix}\right.\\ < =>\left[{}\begin{matrix}x=\dfrac{1}{4}\left(TM\right)\\x=9\left(TM\right)\end{matrix}\right.\)
\(\left(b\right):3\sqrt{x}+5< 6\\ < =>3\sqrt{x}< 1\\ < =>\sqrt{x}< \dfrac{1}{3}\\ < =>0\le x< \dfrac{1}{9}\)
\(\left(c\right):x-3\sqrt{x}-10< 0\\ < =>\left(x-5\sqrt{x}\right)+\left(2\sqrt{x}-10\right)< 0\\ < =>\sqrt{x}\left(\sqrt{x}-5\right)+2\left(\sqrt{x}-5\right)< 0\\ < =>\left(\sqrt{x}-5\right)\left(\sqrt{x}+2\right)< 0\\ =>\left\{{}\begin{matrix}\sqrt{x}-5< 0\\\sqrt{x}+2>0\end{matrix}\right.\\ < =>\left\{{}\begin{matrix}0\le x< 25\\x\ge0\end{matrix}\right.< =>0\le x< 25\)
\(\left(d\right):x-5\sqrt{x}+6=0\left(x\ge0\right)\\ < =>\left(x-2\sqrt{x}\right)-\left(3\sqrt{x}-6\right)=0\\ < =>\sqrt{x}\left(\sqrt{x}-2\right)-3\left(\sqrt{x}-2\right)=0\\ < =>\left(\sqrt{x}-3\right)\left(\sqrt{x}-2\right)=0\\ =>\left[{}\begin{matrix}\sqrt{x}-3=0\\\sqrt{x}-2=0\end{matrix}\right.\\ < =>\left[{}\begin{matrix}x=9\\x=4\end{matrix}\right.\left(TM\right)\)
\(\left(e\right):x+5\sqrt{x}-14< 0\\ < =>\left(x+7\sqrt{x}\right)-\left(2\sqrt{x}+14\right)< 0\\ < =>\sqrt{x}\left(\sqrt{x}+7\right)-2\left(\sqrt{x}+7\right)< 0\\ < =>\left(\sqrt{x}-2\right)\left(\sqrt{x}+7\right)< 0\\ =>\left\{{}\begin{matrix}\sqrt{x}+7>0\\\sqrt{x}-2< 0\end{matrix}\right.\\ < =>\left[{}\begin{matrix}x\ge0\\0\le x< 4\end{matrix}\right.< =>0\le x< 4\)
tìm x, biết
a) (x+5).9x-4)=0
b) (x-1).(x-3)=0
c) (3-x).(x-3)=0
d) x.(x+1)=0
a) (x+5)(x-4)=0
<=> x+5=0 hoặc x-4=0
<=> x=-5 hoặc x=4
b) (x-1)(x-3)=0
<=> x-1=0 hoặc x-3=0
<=> x=1 hoặc x=3
a) (x+5).(9x-4)=0
=> x+5=0 hoặc 9x-4=0
Nếu x+5=0: x=0-5=-5
Nếu 9x-4=0: 9x=0+4=4
x=4/9
b) (x-1).(x-3)=0
=> x-1=0 hoặc x-3=0
Nếu x-1=0: x=0+1=1
Nếu x-3=0: x=0+3=3
c) (3-x).(x-3)=0
=> 3-x=0 hoặc x-3=0
Nếu 3-x=0: x=3-0=0
Nếu x-3=0: x=0+3=3
d) x.(x+1)=0
=> x=0 hoặc x+1=0
Nếu x+1=0: x=0-1=-1
\(a,\left(x+5\right)\left(9x-4\right)=0\)
<=>\(\orbr{\begin{cases}x+5=0\\9x-4=0\end{cases}}\)
<=>\(\orbr{\begin{cases}x=-5\\x=\frac{4}{9}\end{cases}}\)
\(b,\left(x-1\right)\left(x-3\right)=0\)
<=>\(\orbr{\begin{cases}x-1=0\\x-3=0\end{cases}}\)
<=>\(\orbr{\begin{cases}x=1\\x=3\end{cases}}\)
\(c,\left(3-x\right)\left(x-3\right)=0\)
<=>\(\orbr{\begin{cases}3-x=0\\x-3=0\end{cases}}\)
<=>\(\orbr{\begin{cases}x=3\\x=3\end{cases}}\)
\(d,x\left(x+1\right)=0\)
<=>\(\orbr{\begin{cases}x=0\\x+1=0\end{cases}}\)
<=>\(\orbr{\begin{cases}x=0\\x=-1\end{cases}}\)
Tìm x biết:
a/(x+5).(x-4)=0 b/(x-10).(x-3)=0 c/(3-x).(x-3)=0 d/x.(x+1)=0
Giải hẳn ra
a) (x + 5)(x - 4) = 0
x + 5 = 0 hoặc x - 4= 0
x thuộc {-5 ; 4}
b) (x - 10)(x- 3) = 0
x - 10 = 0 hoặc x - 3 = 0
x thuộc {3;10}
c) (3 - x)(x - 3) = 0
3 - x = 0 ; x - 3 = 0
< = . x= 3 (thõa mãn cả 2 ĐK)
d) x(x + 1) = 0
x = 0 hoặc x+ 1 = 0
=> x = -1
Vậy x thuộc {-1 ; 0}
a)(x+5)(x-4)=0
nên x+5=0 hoặc x-4=0
x=0-5 x=0+4
x=-5 x=4
b)(x-10)(x-3)=0
nên x-10=0 hoặc x-3=0
x=0+10 x=0+3
x=10 x=3
c)(3-x)(x-3)=0
nên 3-x=0 hoặc x-3=0
x=3-0 x=0+3
x=3
d)x(x+1)=0
nên x=0 hoặc x+1=0
x=0-1
x=-1
a/(x + 5).(x - 4) = 0
=> x + 5 = 0 => x = -5
hoặc x - 4 = 0 => x = 4
Vậy x = -5 , x = 4
b/(x - 10).(x - 3) = 0
=> x - 10 = 0 => x = 10
hoặc x - 3 = 0 => x = 3
Vậy x = 10, x = 3
c/(3 - x).(x - 3) = 0
=> (3 - x)2 = 0 => 3 - x = 0 => x = 3
Vậy x = 3
d/x.(x + 1) = 0
=> x = 0
hoặc x + 1 = 0 => x = -1
Vậy x = 0 , x = -1
1, Tìm x, biết
a, | x + 1 | + | x + 2| + | x + 3 | = x
b, | x - 3 | + | x - 1 | =3
2, Cho M = x + 2 \ x - 3
a, Tìm x để M = 0
b, Tìm x để M < 0
c, Tìm x để M > 0
\(a,\left(x+2\right)^{10}+\left(x+2\right)^8=0\\ \Leftrightarrow\left(x+2\right)^8\left[\left(x+2\right)^2+1\right]=0\\ \Leftrightarrow\left[{}\begin{matrix}\left(x+2\right)^8=0\\\left(x+2\right)^2+1=0\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x+2=0\\\left(x+2\right)^2=-1\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=-2\\x\in\varnothing\end{matrix}\right.\\ b,\left(x+3\right)^{10}-\left(x+3\right)^8=0\\ \Leftrightarrow\left(x+3\right)^8\left[\left(x+3\right)^2-1\right]=0\\ \Leftrightarrow\left[{}\begin{matrix}\left(x+3\right)^8=0\\\left(x+3\right)^2-1=0\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x+3=0\\\left(x+3\right)^2=1\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=-3\\x+3=1\\x+3=-1\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-3\\x=-2\\x=-4\end{matrix}\right.\)