1) g(x) = x^2 - 4x + 1
Xв = -b/2a = - -4/2*1 = 2
Yв = 2^2 - 4*2 + 1 = -3
(2; -3)
2) g(x) = x^2 + 6x
Хв = -b/2a = - 6/2*1 = -3
Yв = (-3)^2 + 6*(-3) = -9
(-3; -9)
3) g(x) = 10 - 2x + 5x^2
Xв = -b/2a = - -2/2*5 = 1/5
Yв = 10 - 2*1/5 + 5*(1/5)^2 = 8 4/5
(1/5; 8 4/5)
4) g(x) = 3 - x - x^2
Xв = -b/2a = - -1/2*(-1) = -1/2
Yв = 3 - (-1/2) - (-1/2)^2 = 3 + 1/2 - 1/4 = 3 1/4
(-1/2; 3 1/4)
А) 2y+1x
B)13b+6b+1-b+5=18b+6
C)18a+30-7=18a+23
Ответ:
.................................
AB=6
AD=18
BC=12
sinA=1/3
h=BE - ВЫСОТА
sinA=h/AB , h=ABsinA=6x1/3=2
S=((12+18)/2)×2=30
Это знаменитая формула разности квадратов двух выражений:
a^2 - b^2 = (a-b)(a+b)