help me pls i will give you 5* if u help me thực hiện phép nhân (2b^2 – 2 – 5b + ^b^2)(3 + 3b^2 – b) 31/07/2021 Bởi Melody help me pls i will give you 5* if u help me thực hiện phép nhân (2b^2 – 2 – 5b + ^b^2)(3 + 3b^2 – b)
`(2b^2 – 2- 5b + 6b^2)(3 + 3b^2 -b)` `= 2b^2( 3+ 3b^2 – b) – 2(3 + 3b^2 -b) – 5b( 3 + 3b^2 -b) + 6b^2( 3 + 3b^2 -b)` `=( 6b^2 + 6b^4 – 2b^3) – (6 + 6b^2 – 2b) – (15b + 15b^3 – 5b^2 )+ ( 18b^2 + 18b^4 – 6b^3)` `= 6b^2 + 6b^4 – 2b^3 – 6 – 6b^2 + 2b – 15b – 15b^3 + 5b^2 +18b^2 + 18b^4 – 6b^3` `= ( 6b^2 – 6b^2 + 5b^2 + 18b^2) + (18b^4 + 6b^4) – (2b^3 + 15b^3 + 6b^3) – 6 + (2b – 15b)` `= 23b^2 + 24b^4 – 23b^3 -6 – 13b` Bình luận
Đáp án: `(2b² -2-5b +6b²)(3+3b²-b)` `=(8b² -2-5b)(3+3b²-b)` `= 24b² +24b⁴ -8b³ -6-6b² +2b -15b -15b³ +5b²` `= 24b⁴ +(-8b³ -15b³)+ (24b²-6b²+5b²)+(2b-15b)-6` `= 24b⁴ -23b³ +23b² -13b -6` Bình luận
`(2b^2 – 2- 5b + 6b^2)(3 + 3b^2 -b)`
`= 2b^2( 3+ 3b^2 – b) – 2(3 + 3b^2 -b) – 5b( 3 + 3b^2 -b) + 6b^2( 3 + 3b^2 -b)`
`=( 6b^2 + 6b^4 – 2b^3) – (6 + 6b^2 – 2b) – (15b + 15b^3 – 5b^2 )+ ( 18b^2 + 18b^4 – 6b^3)`
`= 6b^2 + 6b^4 – 2b^3 – 6 – 6b^2 + 2b – 15b – 15b^3 + 5b^2 +18b^2 + 18b^4 – 6b^3`
`= ( 6b^2 – 6b^2 + 5b^2 + 18b^2) + (18b^4 + 6b^4) – (2b^3 + 15b^3 + 6b^3) – 6 + (2b – 15b)`
`= 23b^2 + 24b^4 – 23b^3 -6 – 13b`
Đáp án:
`(2b² -2-5b +6b²)(3+3b²-b)`
`=(8b² -2-5b)(3+3b²-b)`
`= 24b² +24b⁴ -8b³ -6-6b² +2b -15b -15b³ +5b²`
`= 24b⁴ +(-8b³ -15b³)+ (24b²-6b²+5b²)+(2b-15b)-6`
`= 24b⁴ -23b³ +23b² -13b -6`