15x²+19x+4=0
D=19²-4*4*15=361-240=121=11²
x²-6x+8=0
x₁+x₂=-b
x₁x₂=c
x₁+x₂=6
x₁x₂=8
x₁=4
x₂=2
3x²=x+4
3x₂-x-4=0
D=(-1)²-4*(-4)*3=1+48=49=7²
4x²+x-5=0
D=1-4*(-5)*4=1+80=81=9²
2x²-6x+5=0
D=(-6)²-4*5*2=36-40= - 4<0
D<0 - корней нет.
1) (58 4:15 + 56 7:24): 0,8 +2 1:9 *0,225: 8 3:4*3:5 = (874:15+ 1351:24): 2/5 + 19 : 9*9 : 40 : 35 : 4*3 : 5= (41241/360: 2/5 + 19/40) / 21/4 = (41241/144+ 19/40) / 21/4 = 68849/240 : 21/4= 68849/1260= 54 809/1260
2) (7 1/9 - 2 14/15) : (2 2/3 + 1 3/5) - (3/4-1/20) * (5/7 - 5/14) -48 = (64/9 - 44/15): (8/3 + 8/5) - 7/10*5/14 - 48 = 564/135 : 64/15 - 1/4 - 48 = 47/48 - 1/4 -48 = 35/48 - 48 = - 47 13/48
какой именно номер нужно??
X^3-x^2+2=0
x^2*(x-1)=-2
x=-1