4) \(71+\left(x-16\div2^2\right)=75\)
\(x-16\div4=75-71\)
\(x-16\div4=4\)
\(x-4=4\)
\(x=4+4\)
\(x=8\)
5) \(\left[43-\left(56-x\right)\right].12=384\)
\(\left[43-\left(56-x\right)\right]=384\div12\)
\(\left[43-\left(56-x\right)\right]=32\)
\(56-x=43-32\)
\(56-x=11\)
\(x=56-11\)
\(x=45\)
6) \(3^x.2+15=33\)
\(3^x.2=33-15\)
\(3^x.2=18\)
\(3^x=18\div2\)
\(3^x=9\)
\(3^x=3^2\)
\(x=2\)
7) nhỏ quá mk không thấy được lũy thừa
8) \(3^x+4^2=\left(8-3\right)^2\)
\(3^x+4^2=5^2\)
\(3^x=5^2-4^2\)
\(3^x=9\)
\(3^x=3^2\)
\(x=2\)
9) \(\left(2x-3\right)^3=27\)
\(\left(2x-3\right)^3=3^3\)
\(2x=3+3\)
\(2x=6\)
\(x=6\div2\)
\(x=3\)
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