X⁴-11x²+30=0 D=121-120=1 √D=1 x²=1/2[11+1]=6
x²=1/2[11+1]=5 x1=√6 x2=-√6 x3=√5 x4=-√5
2x⁴-5x²+2=0 D=25-16=9 √D=3
x²=1/4[5+3]=2 x²=1/4[5-3]=0.5
x1=√2 x2=-√2 x3=√0.5 x4=-√0.5
<span>8,4х+3-5(7,2х+0,3) = 8,4х+3 -36х -1,5= -27,6х +1,5</span>
<span>при х = 2/3</span>
<span>-27,6 х 2/3 +1,5 = -27 6/10 х 2/3 + 1 5/10= - 27 3/5 х 2/3 +1 1/2= -138/5 х 2/3 +3/2= -92/5 +3/2 = (-184 +15)/10 = -169/10= -16,9</span>
0,2х+(5000-х)0,15=850 0,2х+750-0,15х=850 0,05х=100 х=2000 2000-на 20% 3000-на15%
Корень уравнения:
х=-34/9*9/2
х=-17