\frac{-5(7-2)}{2}=5-\frac{3x}{4}…/*4
\frac{4*(-5)*4}{2}=4*5-\frac{4*3x}{4}
2*(-20)=20-3x
-40=20-3x
3x=20+40
3x=60
x=20
…
4(x+3)-2 \geq -6
4x+12-2\geq-6
4x+10\geq-6
4x\geq-6-10
4x\geq-16
x\geq-4
…
F=\frac{mV^2}{2y}…|*2y
2yF=mV^2
mV^2=2yF
V^2=\frac{2yF}{m}
V=\sqrt{\frac{2yF}{m}}
…
\left \{ {{x-y=5} \atop {3x+4y=8}} \right.
\left \{ {{x=5+y} \atop {3(5+y)+4y=8}} \right.
\left \{ {{x=5+y} \atop {15+3y+4y=8}} \right.
\left \{ {{x=5+y} \atop {15+7y=8}} \right.
\left \{ {{x=5+y} \atop {7y=8-15}} \right.
\left \{ {{x=5+y} \atop {7y=-7}} \right.
\left \{ {{x=5+y} \atop {y=-1}} \right.
\left \{ {{x=5+(-1)} \atop {y=-1}} \right.
\left \{ {{x=5-1} \atop {y=-1}} \right.
\left \{ {{x=4} \atop {y=-1}} \right.
…
\left \{ {{2x-y=4} \atop {-7+y=-7}} \right.
…dodajemy stronami
2x-7=-3
2x=-3+7
2x=4
x=2
podstawiamy do równania początkowego
2x-y=4
2*2-y=4
4-y=4
-y=4-4
y=0
…
x=2
y=0