Y=5-4x
3x+5(5-4x)= -9
3x+25-20x = -9
-17x=-34
x=2
Решение во вложенииииииииииииииииииииииииииииииииии
2x+3y = -11
2x-3y = 7
2x+3y+2x-3y = -11 + 7
2x + 2x = -4
4x = -4
x = -1
2*-1 - 3y = -11
-2 - 3y = -11
-3y = -11 + 2
-3y = -9
y = 3
3x²-x-2=0
d=b²-4ac=(-1)²-4*3*(-2)=1+24=25
√d=√25=5
x1=(-b+√d)/2a=1+5/6=6/6=1
x2=(-b-√d)/2a=1-5/6=-4/6=-2/3
<span>Ответ:x1=1</span>
<span>27500000000=2,75*10¹⁰</span>