1. SHTQ : \(C^k_{10}\cdot\left(x^2\right)^{10-k}\left(-2x\right)^k=C^k_{10}\cdot\left(-2\right)^kx^{20-k}\)
20 - k =16 => k = 4
Số hạng : \(C^4_{16}\cdot\left(-2\right)^4x^{16}\)
2. SHTQ : \(C^k_{12}\cdot\left(3x\right)^{12-k}\cdot\left(-x^2\right)^k=C^k_{12}\cdot3^{12-k}\cdot\left(-1\right)^k\cdot x^{12+k}\)
12 + k = 15 => k = 3
Số hạng : \(-C^3_{12}\cdot3^9\cdot x^{15}\)
3. SHTQ : \(C^k_{11}\cdot\left(-3x\right)^k\)
k = 6
Số hạng : \(C^6_{11}\cdot3^6\cdot x^6\)