Toán P(x) = -2×2 + 3×2 – x3 – x2 + 2 và Q(x) = -3×3 + x2 – 1. P(x) – Q(x) là đa thức : 25/07/2021 By Genesis P(x) = -2×2 + 3×2 – x3 – x2 + 2 và Q(x) = -3×3 + x2 – 1. P(x) – Q(x) là đa thức :
Đáp án: `P (x) – Q (x) = (-2x^2 + 3x^2 – x^3 – x^2 + 2) – (-3x^3 + x^2 – 1)` `-> P (x) – Q (x) =-2x^2 + 3x^2 – x^3 – x^2 + 2 + 3x^3 – x^2 + 1` `-> P (x) – Q (x) = (-2x^2 + 3x^2 – x^2 – x^2) + (-x^3 + 3x^3) + (2 + 1)` `-> P (x) – Q (x) = -x^2 + 2x^3 + 3` `text{Vậy}` `P (x) – Q (x) = -x^2 + 2x^3 + 3` Trả lời
`P(x) = -2x^2 + 3x^2 – x^3 – x^2 + 2` `= -x^3 + (-2x^2 + 3x^2 – x^2) + 2` `= -x^3 + 2` `Q(x) = -3x^3 + x^2 – 1` `⇒ P(x) – Q(x) = (-x^3 + 2) – (-3x^3 + x^2 – 1)` `= -x^3 + 2 + 3x^3 – x^2 + 1` `= (-x^3 + 3x^3) – x^2 + (2 + 1)` `= 2x^3 – x^2 + 3` Vậy `P(x) – Q(x) = 2x^3 – x^2 + 3` Trả lời
Đáp án:
`P (x) – Q (x) = (-2x^2 + 3x^2 – x^3 – x^2 + 2) – (-3x^3 + x^2 – 1)`
`-> P (x) – Q (x) =-2x^2 + 3x^2 – x^3 – x^2 + 2 + 3x^3 – x^2 + 1`
`-> P (x) – Q (x) = (-2x^2 + 3x^2 – x^2 – x^2) + (-x^3 + 3x^3) + (2 + 1)`
`-> P (x) – Q (x) = -x^2 + 2x^3 + 3`
`text{Vậy}` `P (x) – Q (x) = -x^2 + 2x^3 + 3`
`P(x) = -2x^2 + 3x^2 – x^3 – x^2 + 2`
`= -x^3 + (-2x^2 + 3x^2 – x^2) + 2`
`= -x^3 + 2`
`Q(x) = -3x^3 + x^2 – 1`
`⇒ P(x) – Q(x) = (-x^3 + 2) – (-3x^3 + x^2 – 1)`
`= -x^3 + 2 + 3x^3 – x^2 + 1`
`= (-x^3 + 3x^3) – x^2 + (2 + 1)`
`= 2x^3 – x^2 + 3`
Vậy `P(x) – Q(x) = 2x^3 – x^2 + 3`