{2x+3y=-7{x-y=4 => x=y+42(y+4)+3y=-72y+8+3y=-75y=-15y=-3x=-3+4=1Ответ: (1;-3)
<span>6 * х + 5 *(х-2)=3х(х-2)</span>
<span>6x+5x-10=3x²-6x</span>
<span>3x²-17x+10=0</span>
<span>D=289-120=169</span>
<span></span>
<span><span>3*х+8*(х-5)=2х*(х-5)</span></span>
<span><span>3x+8x-40=2x²-10x</span></span>
<span><span>2x²-21x+40=0</span></span>
<span><span>D=441-320=121</span></span>
tgx=+-sqrt(1/3)
x1=П/6+Пn. где n целое
х2=-П/6+Пk. где k целое