Odpowiedź:
ZAD. 1
a) (2a + 3)(3b +4) = 6ab + 8a + 9b + 12
b) (-5c + 2)(6d - 1) = -30cd + 5c + 12d - 2
c) (a – 2b)(5a + 3b) = 5a2 + 3ab – 10ab – 6b2 = -7ab + 5a^2 – 6b^2
d) (5c +4)^2 = 25c^2 + 40c + 16
e) (3x + 6y)(2x + 3y - 4)= 6x^2 + 9xy - 12x + 12xy + 18y^2 - 24y = 6x^2 + 21xy - 12x + 18^2 - 24y
ZAD. 2
a) (x^2 + 1) - ( x^2 - x) + 10 = x^2 + 1 - x^2 + x + 10 = 1 + x + 10 = 11 + x
x= 2,2
11 + 2,2 = 13,2
b) 6(a + 3b) + 3(2a - 5b) = 6a + 18b + 6a - 15b = 12a + 3b
a= 0,5 b= -2
12 * 0,5 + 3 * (-2) = 6 + (-6) = 0
