( 3.x – 18).( x – 9) = 0
( 3 x X - 18 ) x ( X - 9 ) = 0
bạn tách ra như thế này nhá : +)
3 x X = 18 = 0
3 x X = 0 +18
3 x X = 18
X = 18 :3
X =6
+) x - 9 = 0
x = 0 + 9
x = 9
vậy x = 6 hoac 9
=>( 3X - 18 ) x ( X - 9 ) = 0
=> \(\hept{\begin{cases}3x-18=0\\x-9=0\end{cases}}\)=> x=6 hoặc x=9
Câu 15: Tìm x thuộc bội của 9 và x < 63
A. x ∈ {0; 9; 18; 27; 36; 45; 54} B. x ∈ {0; 9; 18; 28; 35}
C. x ∈ {9; 18; 27; 36; 45; 54; 63} D. x ∈ {9; 18; 27; 36; 45; 55; 63}
(3.x-18).(x-9)=0
\(\left(3x-18\right)\left(x-9\right)=0\)
\(\Rightarrow\orbr{\begin{cases}3x-18=0\\x-9=0\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}3x=18\\x=9\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}x=6\\x=9\end{cases}}\)
( 3.x-18).(9-x)=0
( 3x - 18) . (9 - x) = 0
\(\Rightarrow\hept{\begin{cases}3x-18=0\\9-x=0\end{cases}\Rightarrow\hept{\begin{cases}x=6\\x=9\end{cases}}}\)
( 3.x-18).(9-x)=0
<=>3x-18=0 hoặc 9-x=0
TH1: 3x-18=0
<=>3x=18
<=>x=6
Th2 :x-9=0
<=>x=9
vậy x=6 hoặc x=9
k mk nha mk mk bị âm điểm rùi
Ta có: ( 3.x - 18) . (9 - x) = 0
\(\Leftrightarrow\orbr{\begin{cases}3x-18=0\\9-x=0\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}3x=0+18\\x=9-0\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}3x=18\\x=9\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=6\\x=9\end{cases}}\)
tìm x thuộc Z:
a, -154+(x-9-18)=40
b,/9-x/=64+(-7)
c, -(-x+13.142)+18=55
d,(x-7).(x+1)=0
e,(x-7).(x+1)>0
f, (x-3).(x^2+5)=0
a, -154+(x-9-18)=40
x-27=40-(-154)
x-27=194
x=194+27
x=221
b,\(\left|9-x\right|\)=64+(-7)
\(\left|9-x\right|\)=57
TH1:
9-x=57
x=9-57
x=-48
TH2:
9-x=-57
x=9-(-57)
x=66
a, -154+(x-9-18)=40
x-27=40-(-154)
x-27=194
x=194+27
x=221
b,|9−x||9−x|=64+(-7)
|9−x||9−x|=57
TH1:
9-x=57
x=9-57
x=-48
TH2:
9-x=-57
x=9-(-57)
x=66
Tìm x
x^2 - 4x = 0
4x^2 - 9 = 0
2x ( x - 3 ) + 5( x - 3 ) = 0
x ( 2x + 9 )- 4x - 18
( 2x - 1 )^2 - ( x + 2 )^2 = 0
a) \(x^2-4x=0\)
\(x\left(x-4\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x=0\\x-4=0\end{cases}\Rightarrow\orbr{\begin{cases}x=0\\x=4\end{cases}}}\)
b) \(4x^2-9=0\)
\(\left(2x\right)^2-3^2=0\)
\(\left(2x+3\right)\left(2x-3\right)=0\)
\(\Rightarrow\orbr{\begin{cases}2x+3=0\\2x-3=0\end{cases}\Rightarrow\orbr{\begin{cases}x=\frac{-3}{2}\\x=\frac{3}{2}\end{cases}}}\)
c) \(2x\left(x-3\right)+5\left(x-3\right)=0\)
\(\left(x-3\right)\left(2x+5\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x-3=0\\2x+5=0\end{cases}\Rightarrow\orbr{\begin{cases}x=3\\x=\frac{-5}{2}\end{cases}}}\)
d) \(x\left(2x+9\right)-4x-18=0\)
\(x\left(2x+9\right)-2\left(2x+9\right)=0\)
\(\left(2x+9\right)\left(x-2\right)=0\)
\(\Rightarrow\orbr{\begin{cases}2x+9=0\\x-2=0\end{cases}\Rightarrow\orbr{\begin{cases}x=\frac{-9}{2}\\x=2\end{cases}}}\)
e) \(\left(2x-1\right)^2-\left(x+2\right)^2=0\)
\(\left(2x-1-x-2\right)\left(2x-1+x+2\right)=0\)
\(\left(x-3\right)\left(3x+1\right)=0\)
\(\Rightarrow\orbr{\begin{cases}x-3=0\\3x+1=0\end{cases}\Rightarrow\orbr{\begin{cases}x=3\\x=\frac{-1}{3}\end{cases}}}\)
\(x^2-4x=0\)
\(x.\left(x-4\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}x=0\\x-4=0\Leftrightarrow x=4\end{cases}}\)
\(4x^2-9=0\)
\(2^2x^2-9=0\)
\(\left(2x\right)^2-9=0\)
\(\left(2x\right)^2-3^2=0\)
\(\Rightarrow\orbr{\begin{cases}\left(2x\right)^2=\left(-3\right)^2\\\left(2x\right)^2=3^2\end{cases}\Rightarrow\orbr{\begin{cases}2x=-3\\2x=3\end{cases}\Rightarrow\orbr{\begin{cases}x=\frac{-3}{2}\\x=\frac{3}{2}\end{cases}}}}\)
\(2x\left(x-3\right)+5\left(x-3\right)=0\)
\(\left(x-3\right)\cdot\left(2x+5\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}\left(x-3\right)=0\\2x+5=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=0+3\\2x=-5\end{cases}\Leftrightarrow\orbr{\begin{cases}x=3\\x=\frac{-5}{2}\end{cases}}}\)
\(x\left(2x+9\right)-4x-18=0\)
\(x\left(2x+9\right)-\left(4x+18\right)=0\)
\(x\left(2x+9\right)-\left(2\cdot2x+2\cdot9\right)=0\)
\(x\left(2x+9\right)-2.\left(2x+9\right)=0\)
\(\left(2x+9\right)\left(x-2\right)=0\Leftrightarrow\orbr{\begin{cases}2x+9=0\\x-2=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}2x=-9\\x=0+2\end{cases}\Leftrightarrow\orbr{\begin{cases}x=\frac{-9}{2}\\x=2\end{cases}}}\)
\(\left(2x-1\right)^2-\left(x+2\right)^2=0\)
\(\Rightarrow\left(2x-1\right)^2=\left(x+2\right)^2\)
\(\Rightarrow\orbr{\begin{cases}2x-1=x+2\\2x-1=-x+2\end{cases}\Rightarrow\orbr{\begin{cases}2x=3+x\\2x=-x+3\end{cases}\Rightarrow\orbr{\begin{cases}2x-x=3\\2x+x=3\end{cases}\Rightarrow\orbr{\begin{cases}x=3\\x=1\end{cases}}}}}\)
\(\)
tìm x thuộc c biết
1) 7-(18+x)= - 15
2) (x-17)-(-3)=0
3) -18-(x-6)=0
4) 29-(10+29)=x-(27-9)
1,7-(18+x)=-15
<=>18+x=7+15
<=>18+x=22
<=>x=4
2,(x-17)-(-3)=0
<=>x-17+3=0
<=>x-17=-3
,<=>x=14
<=>
1,
7 - ( 18 + x ) = - 15
18 + x = 7 + 15
18 + x = 22
x = 22 - 18
x = 4
2,
( x - 17 ) - ( - 3 ) = 0
( x - 17 ) + 3 = 0
x - 17 = - 3
x = -3 + 17
x = 14
3, -18 - ( x - 6 ) = 0
-18 = x- 6
x = - 18 + 6
x = - 12
4, 29 - ( 10 + 29 ) = x - ( 27 - 9 )
-10 = x - 18
x = - 10 + 18
x = 8
( 3.x – 18).( x – 9) = 0
(3x-18)(x-9)=0
\(\Leftrightarrow\left[{}\begin{matrix}3x-18=0\\x-9=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}3x=18\\x-9=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=6\\x=9\end{matrix}\right.\)
Vậy để giá trị của biểu thức bằng 0 thì x=6 hoặc x=9
So sánh a, (-12) x 1125 x (-9) x(-5).3 với 0
b, 21.(-25).(-6).(-3).18.(-2022) với 0\(a,\left(-12\right).1125.\left(-9\right).\left(-5\right).3=-1822500< 0\)
\(b,21.\left(-25\right).\left(-6\right).\left(-3\right).18.\left(-2022\right)=343942200>0\)