1) a) $$1,5x\cdot8x = 1,5\cdot8\cdot x\cdot x = 12x^2$$
б) $$-a^2\cdot4a^3 = -4\cdot a^2\cdot a^3 = -4a^{2+3} = -4a^5$$
в) $$6y\cdot(-\frac{1}{3}y^2) = 6\cdot(-\frac{1}{3})\cdot y\cdot y^2 = -2y^{1+2} = -2y^3$$
2) a) $$\frac{2}{3}a\cdot12ab^2 = \frac{2}{3}\cdot12\cdot a\cdot a\cdot b^2 = 8a^2b^2$$
б) $$0,5x^2y\cdot(-xy) = 0,5\cdot(-1)\cdot x^2\cdot x\cdot y\cdot y = -0,5x^3y^2$$
в) $$-0,4x^4y^2\cdot2,5x^2y^4 = -0,4\cdot2,5\cdot x^4\cdot x^2\cdot y^2\cdot y^4 = -1x^{4+2}y^{2+4} = -x^6y^6$$
Ответ: 1) a) $$12x^2$$; б) $$-4a^5$$; в) $$-2y^3$$; 2) a) $$8a^2b^2$$; б) $$-0,5x^3y^2$$; в) $$-x^6y^6$$