Tìm x biết:
a ) x/-15=-60/x
b) -2/x=-x/8/25
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a) x-(-25+x)=13-x
⇒ x+25-x=13-x
⇒ 13-x=25
⇒ x= -12
b) 15-(30+x)=x-(27-l-8l)
⇒ 15-30-x=x-(27-8)
⇒ -15-x=x-19
⇒ -x-x=-19+15
⇒ -2x+4=0
⇒ -2x=-4
⇒ x=2
c) (12x-43).83=4.84
⇒ 12x.83-43.83=4.84
⇒ 6144x-32768=16384
⇒ 6144x=49152
⇒ x=8
a: Ta có: \(x-\left(-25+x\right)=13-x\)
\(\Leftrightarrow13-x=25\)
hay x=-12
b: Ta có: \(15-\left(30+x\right)=x-\left(27-\left|-8\right|\right)\)
\(\Leftrightarrow-15-x=x-19\)
\(\Leftrightarrow-2x=-4\)
hay x=2
c: Ta có: \(\left(12x-4^3\right)\cdot8^3=4\cdot8^4\)
\(\Leftrightarrow\left(12x-64\right)\cdot512=16384\)
\(\Leftrightarrow12x-64=32\)
hay x=8
a,\(\frac{x}{-15}=\frac{-60}{x}\)=\(x^2\)= [-15 ] . [60] = 900 \(\Rightarrow\)x = + 30
a.
\(\frac{x}{-15}=\frac{-60}{x}=x^2=\left(-15\right):\left(60\right)=900\Rightarrow x=+30\)
a.
\(\frac{x}{-15}=-\frac{60}{x}\)
\(x\times x=15\times60\)
\(x^2=900\)
\(x^2=\left(\pm30\right)^2\)
\(x=\pm30\)
Vậy \(x=-30\) hoặc \(x=30\)
b.
\(-\frac{2}{x}=\frac{-x}{\frac{8}{25}}\)
\(x\times x=2\times\frac{8}{25}\)
\(x^2=\frac{16}{25}\)
\(x^2=\left(\pm\frac{4}{5}\right)^2\)
\(x=\pm\frac{4}{5}\)
Vậy \(x=\frac{4}{5}\) hoặc \(x=-\frac{4}{5}\)
Chúc bạn học tốt ^^
a/Theo bài ra ta có x.x= (-15).(-60)= \(x^2\)=900 mà 900= \(30^2\)suy ra x=30
Lời giải:
a.
$23+x=15$
$x=15-23=-8$
b.
$x-18=-23$
$x=-23+18=-5$
c.
$x+(-4)=16$
$x=16-(-4)=16+4=20$
d.
$25-x=-16$
$x=25-(-16)=25+16=41$
e.
$(-35)x=-210$
$x=(-210):(-35)=6$
f.
$(-2)(15-x)=60$
$15-x=60:(-2)=-30$
$x=15-(-30)=15+30=45$
a) \(x^2=\left(-15\right).\left(-60\right)=900=>x=\)\(\pm\)\(30\)
b) \(-x^2=\dfrac{-16}{25}=>x^2=\dfrac{16}{25}=>x=\)\(\pm\)\(\dfrac{4}{5}\)
a)\(\dfrac{x}{-15}\)= \(-\dfrac{60}{x}\)
=> x . x = -15 . (-60)
=> \(^{x^2}\) = 900
x = 30
b) \(-\dfrac{2}{x}\) = \(-\dfrac{x}{\dfrac{8}{25}}\)
=> -2 . \(\dfrac{8}{25}\) = x . (-x)
=> \(\dfrac{-16}{25}\) = \(^{x^2}\)
=> x = \(\dfrac{4}{5}\)và \(-\dfrac{4}{5}\)
nhớ tích cho mk vs nha >_<
a)x/-15=-60/x
<=> x.x=-15.(-60)
2x=900
x=900:2
x=450
vậy x=450
b) -2/x=-x/8
x.(-x)=-2.8
-2x=-16
x=-16:(-2)
x=8
vậy x=8
a) Ta có: x /-15 = -60/x <=> (-15)(-60)= x.x
<=> 900= x^2 => x= -30; 30
b) Ta có : (-2)*8 = x*(-x)
<=> -16= x*(-x) <=> 16= x^2
=> x= -4; 4
a) \(\frac{x}{-15}=-\frac{60}{x}\)
\(\Rightarrow x.x=\left(-60\right).\left(-15\right)\)
\(\Rightarrow x^2=900=30^2\)
\(\Rightarrow x=30\)
b) \(-\frac{2}{x}=-\frac{x}{\frac{8}{25}}\)
\(\Rightarrow x.x=-2.\frac{-8}{25}\)
\(\Rightarrow x^2=\frac{16}{25}=\left(\frac{4}{5}\right)^2\)
\(\Rightarrow x=\frac{4}{5}\)
\(a,\frac{x}{-15}=\frac{-60}{x}\)
\(\Rightarrow x.x=\left(-60\right).\left(-15\right)\)
\(\Rightarrow x^2=900\)
\(\Rightarrow x^2=\orbr{\begin{cases}30^2\\-30^2\end{cases}}\)
\(\Rightarrow x=\orbr{\begin{cases}30\\-30\end{cases}}\)
\(b,\frac{-2}{x}=\frac{-x}{8}:25\)
\(\Rightarrow-x^2=-2.8.25=-400\)
\(\Rightarrow x^2=400\)
\(\Rightarrow x=\orbr{\begin{cases}20\\-20\end{cases}}\)