y=4-x x-2=4-x если x=3, то y=1 (y=4-3/y=3-2)
y=x-2 2x=6
x=3
Ответ:(3;1)
1.5х(х+4)-х(7-0.5х)=0.5(10-2х)=
=1.5х+6х-7х+0.5х=5-х
=1.5х+6х-7х+0.5х+х=5
х=5
S=(ab+bc+ac)=32
S2=(ab/4+bc/4+ac/4)=32
ab+bc+ac =128
===1-cos²60-1-0.25=0.75