Х²-5х+4=0
а=1 b=-5 c=4
D= b²-4ac => D= 25-16 =9
D>0 => 2 корня
Х1, 2 = (- b±корень из D)/2a
X1 =( - 5+3)/2 = 1
X2= (-5-3)/2= - 4
<span>
1/7а²b*23m -2/7a²bm=1/7 a²bm(23 - 2) = 21:7 a²bm = 3a²bm</span>
<span /><span>5а²-2аb+6a-7ab-6a²-6a= -a² -9ab = -a(a +9b)</span>
<span>a=5 b= -1/9</span>
<span>-5(5 -9x1/9) = -20</span>