18-5(x+3)>1-7x
18-5x-15>1-7x
-5x+7x>-18+15+1
2x>-2/2
x>-1
-3х+6+4+8х=10.3+20х
10+5х=10.3+20х
10-10.3=20х-5х
-0.3=15х
х=-0.02
<span>4(y+0,5)-(y-1)=16
4у+2-у+1=16
3у=13
у=4 1/3
</span>
{3х+10 / у+1 = 1/12,
{5х+у / 9х+2у = 4/5,
{12*(3х+10) = у+1,
{5*(5х+у) = 4*(9х+1у),
{36х+120 = у+1,
{25х+5у = 36х+8у,
{36х-у = - 119,
{-11х-3у = 0,
Из 1 уравнения:
у = 36х+119.
Подставим во 2 уравнение :
-11х - 3*(36х+119) = 0,
-11х - 108х - 357 = 0,
-119х = 357,
х = - 3,
у = 36*(-3) + 119 = - 108 + 119 = 11.
Ответ: (-3; 11)