(9a^2-9ab)+(5a-5b)
9a(a-b)-5(a-b)
9a-5
9*2-5=18-5=13 по-моему так
<span>х²-10х-24=0 (a=1; b = -10; c = -24)
D = b</span><span>² - 4ac
D = (-10)</span>² - 4 × 1 × (-24) = 100 + 96 = 196 (√196 = 14)
D <span>> 0
x1 = -b + </span>√D/2a = -(-10) + 14/2×1 = 10 + 14/2 = 24 /2 = 12.
x2 = -b - √D/2a = -(-10) - 14/2 <span>× 1 = 10 - 14/2 = -4/2 = -2.
Сумма корней = 12 + (-2) = 12 - 2 = 10.</span>
Ответ:
1) (c+2)(c-3)=c^2-3c+2c-6=c^2-c-6
2) 25
x
^2
−
4
y^
2
3) (2a-1)(3a+4)=6а^2+8a-3a-4=6a^2+5a-4
4) a^3-5a^2+12a-12
Объяснение: