إذا كان c(x) = x2 – 2x , d(x) = 3x2 – 6x + 4 ، فأوجد قيمة كل مما يأتى
c(a + 2) – d(a – 4)
الاجابة
c(a + 2) = (a + 2)2 – 2(a + 2)
c(a +2) = a2 + 4a + 4 – 2a – 4
c(a + 2) = a2 + 2a
d(a – 4) = 3(a – 4)2 – 6(a – 4) + 4
d(a – 4) = 3(a2 – 8a + 16) -6(a – 4) + 4
d(a – 4) = 3a2 – 24a + 48 – 6a + 24 + 4
d(a – 4) = 3a2 – 30a + 76
c(a + 2) – d(a – 4) = a2 + 2a – 3a2 + 30a – 76
c(a + 2) – d (a – 4) = -2a2 + 32a – 76