5х^2 - 8x+ 3 = 2x^2 - 8x + 5
5x^2 - 8x - 2x^2 + 8x = 5 - 3
3x^2 = 2
x^2 = 2/3
x1 = √2/3
x2 = - √2/3
3/4 * (0,25х + 2/3) = 3х + 1/4 Умножим левую и правую часть уравнения на 4 : 3 *(1/4х + 2/3) = 12х + 1
3/4х + 2 = 12х + 1
2 - 1 = 12х - 3/4х
1 = 11 1/4х
45/4 х = 1
45х = 4
х = 4/45
700:x=630:9
700:x=70
<span>x=700:70=10
ПРОВЕРКА:
700:10=70</span>
X1 = 80, x2 = 0
v1 = 80, v2 = 100
80+80*t = 100*t
80 = 20 t
t = 4ч