a: x=-3/4+2/3=-9/12+8/12=-1/12
b: =>1/4x=-1/8+3/4=5/8
=>x=5/8:1/4=5/2
c: \(\Leftrightarrow3\cdot2^{2n+1}=24\)
=>2n+1=3
hay n=1
\(a,x=\dfrac{-3}{4}-\dfrac{-2}{3}\)
\(x=\dfrac{-9}{12}-\dfrac{-8}{12}\)
\(x=\dfrac{-1}{12}\)
\(b,\dfrac{-3}{4}+\dfrac{1}{4}x=\dfrac{-8}{8}+\dfrac{7}{8}=\dfrac{-1}{8}\)
\(\dfrac{1}{4}x=\dfrac{-1}{8}-\dfrac{-3}{4}\)
\(\dfrac{1}{4}x=\dfrac{-1}{8}-\dfrac{-6}{8}=\dfrac{5}{8}\)
\(x=\dfrac{5}{8}:\dfrac{1}{4}=\dfrac{5}{8}.\dfrac{4}{1}\)
\(x=\dfrac{20}{8}=\dfrac{5}{2}\)
\(c,3.2^{2x+1}=\dfrac{49}{2}-\dfrac{1}{2}=24\)
\(2^{2x+1}=24:3=8\)
\(2^{2x+1}=2^3\)
\(2x+1=3\)
\(2x=3-1=2\)
\(x=2:2\)
\(x=1\)
\(d,\dfrac{5}{2}-3.\left(x+\dfrac{4}{3}\right)=\dfrac{3}{2}\)
\(3.\left(x+\dfrac{4}{3}\right)=\dfrac{5}{2}-\dfrac{3}{2}=1\)
\(x+\dfrac{4}{3}=1:3=\dfrac{1}{3}\)
\(x=\dfrac{1}{3}-\dfrac{4}{3}\)
\(x=\dfrac{-3}{3}=-1\)
e, Tìm x
\(\dfrac{3-x}{12}=\dfrac{192}{-72}\)
\(\left(3-x\right).\left(-72\right)=192.12\)
\(-216+72x=2304\)
\(72x=2304-\left(-216\right)=2520\)
\(x=2520:72\)
\(x=35\)
Tìm y
\(\dfrac{3-35}{12}=\dfrac{16}{y+1}\)
\(\dfrac{-32}{12}=\dfrac{16}{y+1}\)
\(\dfrac{-8}{3}=\dfrac{16}{y+1}\)
\(\left(-8\right).\left(y+1\right)=16.3\)
\(-8y+\left(-8\right)=48\)
\(-8y=48-\left(-8\right)=56\)
\(y=56:\left(-8\right)\)
\(y=-7\)
f,Tim x
\(\dfrac{-\left(x+3\right)}{27}=\dfrac{-121}{33}\)
\(\dfrac{-\left(x+3\right)}{27}=\dfrac{-11}{3}\)
\(-\left(x+3\right).3=\left(-11\right).27\)
\(-x.3+\left(-3\right).3=-297\)
\(-3x+\left(-9\right)=-297\)
\(-3x=\left(-297\right)-\left(-9\right)=-288\)
\(x=\left(-288\right):\left(-3\right)\)
\(x=96\)
Tìm y
\(\dfrac{-\left(96+3\right)}{27}=\dfrac{11}{1-2y}\)
\(\dfrac{-99}{27}=\dfrac{11}{1-2y}\)
\(\dfrac{-11}{3}=\dfrac{11}{1-2y}\)
\(\left(-11\right).\left(1-2y\right)=11.3\)
\(\left(-11\right)-2y.\left(-11\right)=33\)
\(2y.\left(-11\right)=\left(-11\right)-33=-44\)
\(2y=\left(-44\right):\left(-11\right)=4\)
\(y=4:2\)
\(y=2\)
Câu e và câu f mik lúc nãy chx lm đuợc giờ giửi cho bạn 2 cây này
