Toán câu1,(x+1).(x mũ 2 -x+1) caau2, (2x mũ 3-3x-1).(5x+2) caau3,(x mũ 2 -2x+3).(x-4) 25/07/2021 By Aubrey câu1,(x+1).(x mũ 2 -x+1) caau2, (2x mũ 3-3x-1).(5x+2) caau3,(x mũ 2 -2x+3).(x-4)
1 , ( x + 1 ) ( x² – x + 1 ) = x³ – x² + x + x² – x + 1 = x³ + 1 2 , ( 2x³ – 3x – 1 ) ( 5x + 2 ) = 10$x^{4}$ + 4x³ – 15x² – 6x – 5x – 2 = 10$x^{4}$ + 4x³ – 15x² – 11x – 2 3 , ( x² – 2x + 3 ) ( x – 4 ) = x³ – 4x² – 2x² + 8x + 3x – 12 = x³ – 6x² + 11x – 12 4 , ( 2x – 1 ) ( 3x + 2 ) ( 3 – x ) = ( 6x² + 4x – 3x – 2 ) ( 3 – x ) = 18x² – 6x³ + 12x – 4x² – 9x + 3x² – 6 + 2x = -6x³ + 17x² + 5x – 6 chúc em học tốt #anhduongtruong #iloveyouBLACKPINK Trả lời
Đáp án: 1. `(x + 1)(x^2 – x + 1)` ` = x^3 + 1` Áp dụng HĐT :` a^3 + b^3 = (a + b)(a^2 – ab + b^2)` 2. `(2x^3 – 3x – 1)(5x + 2)` ` = 10x^4 – 15x^2 – 5x + 4x^3 – 6x – 2` ` = 10x^4 + 4x^3 – 15x^2 – 11x – 2` 3. `(x^2 – 2x + 3)(x – 4)` ` = x^3 – 2x^2 + 3x – 4x^2 + 8x – 12` ` = x^3 – 6x^2 + 11x – 12` Giải thích các bước giải: Trả lời
1 , ( x + 1 ) ( x² – x + 1 )
= x³ – x² + x + x² – x + 1
= x³ + 1
2 , ( 2x³ – 3x – 1 ) ( 5x + 2 )
= 10$x^{4}$ + 4x³ – 15x² – 6x – 5x – 2
= 10$x^{4}$ + 4x³ – 15x² – 11x – 2
3 , ( x² – 2x + 3 ) ( x – 4 )
= x³ – 4x² – 2x² + 8x + 3x – 12
= x³ – 6x² + 11x – 12
4 , ( 2x – 1 ) ( 3x + 2 ) ( 3 – x )
= ( 6x² + 4x – 3x – 2 ) ( 3 – x )
= 18x² – 6x³ + 12x – 4x² – 9x + 3x² – 6 + 2x
= -6x³ + 17x² + 5x – 6
chúc em học tốt
#anhduongtruong
#iloveyouBLACKPINK
Đáp án:
1. `(x + 1)(x^2 – x + 1)`
` = x^3 + 1`
Áp dụng HĐT :` a^3 + b^3 = (a + b)(a^2 – ab + b^2)`
2. `(2x^3 – 3x – 1)(5x + 2)`
` = 10x^4 – 15x^2 – 5x + 4x^3 – 6x – 2`
` = 10x^4 + 4x^3 – 15x^2 – 11x – 2`
3. `(x^2 – 2x + 3)(x – 4)`
` = x^3 – 2x^2 + 3x – 4x^2 + 8x – 12`
` = x^3 – 6x^2 + 11x – 12`
Giải thích các bước giải: