回答:
#(x ^ 2-15 x + 6)/(2(x-3)(x + 3)^ 2)#
説明:
#x ^ 2 + 6 x + 9 =(x + 3)(x + 3)=(x + 3)^ 2#
#2x ^ 2-18 = 2(x ^ 2-9)= 2(x-3)(x + 3)#
2マスの違い #(a-b)(a + b)= a ^ 2-b ^ 2#
#(x-2)/(x + 3)^ 2-(x + 2)/(2(x-3)(x + 3))#
で乗算 #2(x-3)(x + 3)^ 2#
= #((x-2)(2)(x-3) - (x + 2)(x + 3))/(2(x-3)(x + 3)^ 2)#
括弧を広げる
= #(2(x ^ 2-5 x + 6) - (x ^ 2 + 5 x + 6))/(2(x-3)(x + 3)^ 2)#
括弧をさらに広げる
= #(2x ^ 2-10x + 12-x ^ 2-5x-6)/(2(x-3)(x + 3)^ 2)#
簡素化する
= #(x ^ 2-15 x + 6)/(2(x-3)(x + 3)^ 2)#