回答:
3根是 #x = -3 / 2,1,3 / 2#
注意我找不到长除法符号所以我将在它的位置使用平方根符号。
说明:
#F(X)= 4×^ 3-4倍^ 2-9x + 9#
#F(1)= 4 * 1 ^ 3-4 * 1 ^ 2-9 * 1 + 9 = 4-4-9 + 9 = 0#
这意味着x = 1是根和 #(X-1)# 是这个多项式的一个因素。
我们需要找到其他因素,我们通过将f(x)除以得到 #(X-1)# 找到其他因素。
#{4倍^ 3-4倍^ 2-9x + 9} / {X-1}#
#(X-1)的sqrt(4倍^ 3-4倍^ 2-9x + 9)#
以来 #(X * 4倍^ 2)= 4×^ 3# 我们得到 #4X ^ 2# 作为因素的一个术语
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #4X ^ 2#
#(X-1)的sqrt(4倍^ 3-4倍^ 2-9x + 9)#
我们需要找到其余部分以找到还需要找到的东西。
我们的确是 #4倍^ 2 *(X-1)= 4×^ 3-4倍^ 2#
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #4X ^ 2#
#(X-1)的sqrt(4倍^ 3-4倍^ 2-9x + 9)#
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #4倍^ 3-4倍^ 2#
我们减去这个得到0
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #4X ^ 2#
#(X-1)的sqrt(4倍^ 3-4倍^ 2-9x + 9)#
# # # # # # # # # # # # # # # # # # # # # # # # #ul { - (4x ^ 3-4x ^ 2)}#
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # ## # # # #0X ^ 3-0x ^ 2#
这个零意味着我们没有线性项,并且下一个条款。
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #4x ^ 2 + 0 x#
#(X-1)的sqrt(4倍^ 3-4倍^ 2-9x + 9)#
# # # # # # # # # # # # # # # # # # # # # # # # #ul { - (4x ^ 3-4x ^ 2)}#
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #0X ^ 3-0x ^ 2# #-9x + 9#
#X * -9 = -9x# 所以下一学期是 #-9#
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #4x ^ 2 + 0 x -9#
#(X-1)的sqrt(4倍^ 3-4倍^ 2-9x + 9)#
# # # # # # # # # # # # # # # # # # # # # # # # #ul { - (4x ^ 3-4x ^ 2)}#
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #0X ^ 3-0x ^ 2# #-9x + 9#
#-9 *(x-1)= - 9x + 9#
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #4x ^ 2 + 0 x -9#
#(X-1)的sqrt(4倍^ 3-4倍^ 2-9x + 9)#
# # # # # # # # # # # # # # # # # # # # # # # # #ul { - (4x ^ 3-4x ^ 2)}#
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #0X ^ 3-0x ^ 2# #-9x + 9#
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #ul { - ( - 9x + 9)}#
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #4x ^ 2 + 0 x -9#
#(X-1)的sqrt(4倍^ 3-4倍^ 2-9x + 9)#
# # # # # # # # # # # # # # # # # # # # # # # # #ul { - (4x ^ 3-4x ^ 2)}#
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #0X ^ 3-0x ^ 2# #-9x + 9#
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #ul { - ( - 9x + 9)}#
# # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # # #0#
所以 #(x-1)(4x ^ 2 -9)# 没有提醒(您可以通过扩展来检查)。我们需要完全考虑这一点。
#(4x ^ 2 -9)# 是因子与方格的差异 #(2X-3)*(2×+ 3)#
我们有 #(x-1)*(2x-3)*(2x + 3)= 0#
#2X-3 = 0# 给了我们一个根源 #X = 3/2# 和 #2X + 3 = 0# 给了我们一个根源 #X = -3 / 2#
根源是 #x = -3 / 2,1,3 / 2#