1.Tính
A= \(\frac{4^6.9^5+6^9.120}{-8^4.3^{12}-6^{11}}\)
B=\(1-\frac{1}{1-2^{-1}}+\frac{1}{1+\frac{1}{2^{-1}}}\)
2. Tìm x, biết:
a) \(\left(2x-3\right)^2=36\)
b) \(\left(2x-1\right)^5=243\)
c) \(\left(7x+2\right)^{-1}=3^{-2}\)
d) \(\left(2x-5\right)^{2000}+\left(3y+4\right)^{2002}\le0\)
a) \(\left(2x-3\right)^2=36\)
\(\left(2x-3\right)^2=6^2\)
\(2x-3=6\)
\(2x=9\)
\(x=4,5\)
b) \(\left(2x-1\right)^5=243\)
\(\left(2x-1\right)^5=3^5\)
\(2x-1=3\)
\(2x=4\)
\(x=2\)