Ответ 250 деталей за час!
Р=6+8+10=24см;
S=(6+8):2=7см.кв.;
А)3цел7/15-1цел11/15=52/15-26/15=26/15=1цел11/15;
В)1цел3/10-4/5=13/10-8/10=5/10=1/2
1.
х²+5х+4=0,
Д=5²-4*1*4=25-16=9,
х1=(-5+3)/2=-1,
х2=(-5-3)/2=-4,
х²+6х+4=0,
д=6²-4*1*4=36-16=20,
х1=(-6+2√5)/2 = -3+√5,
х1=(-6-2√5)/2 = -3-√5,
2.
4х²-12х+7 = 4 * (х - [(3+√2)/2]) * (х - [(3-√2)/2]),
3.
(х²-64) / (х²-11х+24) = (х-8)(х+8) / (х-8)(х-3) = (х+8) / (х-3),
4.
√(-2х+3) = х,
-2х + 3 = х²,
х² + 2х - 3 = 0,
д = 2² - 4*1*(-3) = 4 + 12 = 16,
х1 = (-2+4)/2 = 1,
х2 = (-2-4) / 2 = -3
5/7 : 6/7х + 3/7 -1/2 = 1/6
5/7 : 6/7х= 1/6 - 3/7 +1/2
5/7 : 6/7х = 7/42 - 18/42 + 21/42
5/7 : 6/7х=10/42
6/7х=5/7 : 10/42
6/7х=5/7 * 42/10
6/7 х = 6/2
х= 6/2 : 6/7
х= 6/2 * 7/6
х=7/2
х=3 1/2