1146.
1) 4a*(-3ab)=-12a²b
2) -2m²*0.1m⁴n*(-5n³)=m⁶n⁴
3) 0.3a²b⁴*1.2a⁴b=0.36a⁶b⁵
4) -6x³y⁶*1.5xy=-9x⁴y⁷
5) -14b²c⁸d⁹ * 1²/₇ b⁶d³=-14 * ⁹/₇ b⁸c⁸d¹²=-18b⁸c⁸d¹²
6) ⁴/₉ a⁴c* (-12a²c³) * 1.8a⁴b⁵=⁴/₉ * (-12) * 1.8 a¹⁰b⁵c⁴=-9.6a¹⁰b⁵c⁴
7) 3x⁶*(-4x²y)²=3x⁶ * 16x⁴y²=48x¹⁰y²
8) (-xy)³ * (-2x²y²)⁴=-x³y³ * 16x⁸y⁸=-16x¹¹y¹¹