3(0,9x-1)-(x+0,6)=-0.2
2.7x-3-x-0.6=-0.2
2.7x-x=3+0.6-0.2
1.7x=3.4
x=2
2x^2+13x+6=0
a=2, b=13, c=6
Д=b^2-4ac
Д=169-4*2*6
Д=169-48=121
x1,2=-b+- √Д
x1=-13+11/4=0.5
x2=-13-11/4=6
1) ![\(\frac{9}{11}-\frac{9}{22}\cdot 4\frac{4}{9}=\frac{9}{11}-\frac{9}{22}\cdot \frac{40}{9}=\frac{9}{11}-\frac{9\cdot 40}{22\cdot 9}=\frac{9}{11}-\frac{20}{11}=-\frac{11}{11}=-1\)](https://tex.z-dn.net/?f=%5C%28%5Cfrac%7B9%7D%7B11%7D-%5Cfrac%7B9%7D%7B22%7D%5Ccdot%204%5Cfrac%7B4%7D%7B9%7D%3D%5Cfrac%7B9%7D%7B11%7D-%5Cfrac%7B9%7D%7B22%7D%5Ccdot%20%5Cfrac%7B40%7D%7B9%7D%3D%5Cfrac%7B9%7D%7B11%7D-%5Cfrac%7B9%5Ccdot%2040%7D%7B22%5Ccdot%209%7D%3D%5Cfrac%7B9%7D%7B11%7D-%5Cfrac%7B20%7D%7B11%7D%3D-%5Cfrac%7B11%7D%7B11%7D%3D-1%5C%29)
2) ![\(\frac{4,7+3,54}{0,8}=\frac{8,24}{0,8}=10,3\)](https://tex.z-dn.net/?f=%5C%28%5Cfrac%7B4%2C7%2B3%2C54%7D%7B0%2C8%7D%3D%5Cfrac%7B8%2C24%7D%7B0%2C8%7D%3D10%2C3%5C%29)
3) 60 - 12 = 48 (Вт)
4) 50 * 1,609 = 80,45 (км/ч) скорость автомобиля
5) 120 : 250 · 100% = 48% книги прочитала Даша
100% - 48% = 52% книги осталось прочитать Даше
Второй способ:
250 - 120 = 130 (ст) Осталось прочитать Даше
130 : 250 · 100% = 52% книги осталось прочитать Даше