\(4^{x+2}\cdot5\cdot4^x=1280\)
\(\Leftrightarrow4^x\cdot16\cdot5\cdot4^x=1280\)
\(\Leftrightarrow4^{2x}\cdot80=1280\)
\(\Leftrightarrow4^{2x}=16\)
\(\Leftrightarrow4^{2x}=4^2\)
\(\Leftrightarrow2x=2\)
\(\Leftrightarrow x=1\)
vậy........
\(4^{x+2}\cdot5\cdot4^x=1280\)
\(\Leftrightarrow4^x\cdot16\cdot5\cdot4^x=1280\)
\(\Leftrightarrow4^{2x}\cdot80=1280\)
\(\Leftrightarrow4^{2x}=16\)
\(\Leftrightarrow4^{2x}=4^2\)
\(\Leftrightarrow2x=2\)
\(\Leftrightarrow x=1\)
vậy........
4^x+2.5.4^x = 1280
4^x+2.5.4^x = 1280
1280:[109-(3x-7):]=40. Tìm x
4x+2.5.4x=1280
2x+3+2x+1=1280
\(a=\dfrac{1}{5}+\dfrac{1}{10}+\dfrac{1}{20}+....+\dfrac{1}{1280}\)
C= 1/5+1/10+1/20+1/40+1/80+...........+1280
a){100:[45-45:(-9)]-32}.5-2.52
b)(25-16-32).2024
c)(34-42-2023).1280
B=1/5+1/10+1/20+1/40+...+1/1280 tính nhanh.
giup minh voi nhe!!!!!!