Giá của hàng A là 120 000 đồng

hàng B là 200 000 đồng

a) \(\left(2x+1-3x\right)\left(2x+1+3x\right)=0\)

\(\left(-x+1\right)\left(5x+1\right)=0\)

\(x=1;x=\frac{-1}{5}\)

b) \(x=\frac{19}{13};y=\frac{14}{13}\)

\(P=U.I=\frac{U^2}{R}=\frac{5000^2}{25}=10000000W\)

FF'OABA'B'

\(P=U.I=\frac{U^2}{R}=\frac{120^2}{60}=240W\)

\(W=P.t=240.5.60.60=4320000J\)

a)\(R_{12}=\frac{R_1R_2}{R_1+R_2}=\frac{6.4}{6+4}=2,4\Omega\)

b)\(U_1=U_2=U_{12}=6V\)

\(I_1=\frac{U_1}{R_1}=\frac66=1A\)

\(I_2=\frac{U_2}{R_2}=\frac64=1,5A\)

c)\(R_{123}=R_{12}+R_3=2,4+2,6=5\Omega\)

d)\(R_{tm}=\frac{U}{I}=\frac{6}{0,5}=12\Omega\)

\(R_{x}+R_{12}=12\rArr R_{x}=12-2,4=9,6\Omega\)

a) \(W_{đ}=\frac12mv^2=\frac12.2.10^2=100J\)

b) \(W_{t}=W_{đ}=100J\)

c) \(W_{t}=P.h\)

\(\rArr h=\frac{W_{t}}{P}=\frac{100}{2.10}=5\)

d) \(W_{t}=P.h=2.10.2=40J\)

\(W_{đ}=100-40=60J\)

\(W_{đ}=\frac12mv^2=\frac12.2.v^2=60J\)

\(\rArr v^2=60\)

\(\rArr v=7,75\)

a) (x-5)²

b) (-2y-x) . (4y²-2xy+x²)

a) 9x²+12xy+16y²

b)4x²

c)16x²+11

1: 4P+5O₂→2P₂O₅

2: P₂O₅+3H₂O→2H₃PO₄

3: H₃PO₄+3NaOH→Na₃PO₄+3H₂O

4: 2Na₃PO₄+3Ca(OH)₂→Ca₃(PO₄)₂+6NaOH