câu 13 nhé mn ~““DD Question câu 13 nhé mn ~““DD in progress 0 Môn Toán Dâu 4 years 2020-10-17T09:42:13+00:00 2020-10-17T09:42:13+00:00 2 Answers 94 views 0
Answers ( )
13 D
14 C
Câu 14:
`(9 – x^2)(x^2 – 3x + 2) = 0`
`<=> (3 – x)(3 + x)(x^2 – 3x + 2) = 0`
`<=>` \(\left[ \begin{array}{l}3 – x = 0\\3 + x = 0\\x^2 – 3x + 2 = 0 \end{array} \right.\)
`<=>` \(\left[ \begin{array}{l}x = 3\\x = -3\\x = 2\\x = 1\end{array} \right.\)
`=> B = {-3; 1; 2; 3}`