a) \(\left|-7^{50}\right|:7^{48}-\left|6^2\right|\)
\(=7^{50}:7^{48}-6^2\)
\(=7^{50-48}-6^2\)
\(=7^2-6^2\)
\(=49-36\)
\(=13\)
b) \(3x-9=\left|-21\right|\)
\(\Rightarrow3x-9=21\)
\(\Rightarrow3x=21+9\)
\(\Rightarrow3x=30\)
\(\Rightarrow x=30:3\)
\(\Rightarrow x=10\)
Vậy \(x=10\)
c) \(\left|x\right|-3=7\)
\(\Rightarrow\left|x\right|=7+3\)
\(\Rightarrow\left|x\right|=10\)
\(\Rightarrow\left[{}\begin{matrix}x=10\\x=-10\end{matrix}\right.\)
Vậy \(x=10\) hoặc \(x=-10\)
d) \(\left|x-4\right|-2=\left|-5\right|\)
\(\Rightarrow\left|x-4\right|-2=5\)
\(\Rightarrow\left|x-4\right|=5+2\)
\(\Rightarrow\left|x-4\right|=7\)
Xét trường hợp 1: \(x-4=7\)
\(\Rightarrow x=7+4\)
\(\Rightarrow x=11\)
Xét trường hợp 2: \(x-4=-7\)
\(\Rightarrow x=-7+4\)
\(\Rightarrow x=-\left(7-4\right)\)
\(\Rightarrow x=-3\)
Vậy \(x=11\) hoặc \(x=-3\)
a) ∣∣−750∣∣:748−∣∣62∣∣|−750|:748−|62|
=750:748−62=750:748−62
=750−48−62=750−48−62
=72−62=72−62
=49−36=49−36
=13=13
b) 3x−9=|−21|3x−9=|−21|
⇒3x−9=21⇒3x−9=21
⇒3x=21+9⇒3x=21+9
⇒3x=30⇒3x=30
⇒x=30:3⇒x=30:3
⇒x=10⇒x=10
Vậy x=10x=10
c) |x|−3=7|x|−3=7
⇒|x|=7+3⇒|x|=7+3
⇒|x|=10⇒|x|=10
⇒[x=10x=−10⇒[x=10x=−10
Vậy x=10x=10 hoặc x=−10x=−10
d) |x−4|−2=|−5||x−4|−2=|−5|
⇒|x−4|−2=5⇒|x−4|−2=5
⇒|x−4|=5+2⇒|x−4|=5+2
⇒|x−4|=7⇒|x−4|=7
Xét trường hợp 1: x−4=7x−4=7
⇒x=7+4⇒x=7+4
⇒x=11⇒x=11
Xét trường hợp 2: x−4=−7x−4=−7
⇒x=−7+4⇒x=−7+4
⇒x=−(7−4)⇒x=−(7−4)
⇒x=−3⇒x=−3
Vậy x=11x=11 hoặc x=−3
