Trang chủ » Hỏi đáp » Môn Toán a)6x^2 . (2x^3 – 3x^2 + 5x-4) b)( – 1,2x^2) . (2,5x^4 -2x^3+x^2-1,5) 18/08/2023 a)6x^2 . (2x^3 – 3x^2 + 5x-4) b)( – 1,2x^2) . (2,5x^4 -2x^3+x^2-1,5)
Giải đáp: $\begin{array}{l}a)12{x^5} – 18{x^4} + 30{x^3} – 24{x^2}\\b) – 3{x^6} + 2,4{x^5} – 1,2{x^4} + 1,8{x^2}\end{array}$ Lời giải và giải thích chi tiết: $\begin{array}{l}a)6{x^2}.\left( {2{x^3} – 3{x^2} + 5x – 4} \right)\\ = 6{x^2}.2{x^3} – 6{x^2}.3{x^2} + 6{x^2}.5x – 6{x^2}.4\\ = 12{x^5} – 18{x^4} + 30{x^3} – 24{x^2}\\b)\left( { – 1,2{x^2}} \right).\left( {2,5{x^4} – 2{x^3} + {x^2} – 1,5} \right)\\ = – 1,2{x^2}.2,5{x^4} + 1,2{x^2}.2{x^3} – 1,2{x^2}.{x^2} + 1,2{x^2}.1,5\\ = – 3{x^6} + 2,4{x^5} – 1,2{x^4} + 1,8{x^2}\end{array}$ Trả lời
a)12{x^5} – 18{x^4} + 30{x^3} – 24{x^2}\\
b) – 3{x^6} + 2,4{x^5} – 1,2{x^4} + 1,8{x^2}
\end{array}$
a)6{x^2}.\left( {2{x^3} – 3{x^2} + 5x – 4} \right)\\
= 6{x^2}.2{x^3} – 6{x^2}.3{x^2} + 6{x^2}.5x – 6{x^2}.4\\
= 12{x^5} – 18{x^4} + 30{x^3} – 24{x^2}\\
b)\left( { – 1,2{x^2}} \right).\left( {2,5{x^4} – 2{x^3} + {x^2} – 1,5} \right)\\
= – 1,2{x^2}.2,5{x^4} + 1,2{x^2}.2{x^3} – 1,2{x^2}.{x^2} + 1,2{x^2}.1,5\\
= – 3{x^6} + 2,4{x^5} – 1,2{x^4} + 1,8{x^2}
\end{array}$