Solving problems multiplying Polynomials

21xy²

10xy²

21x²y⁴

10x²y⁴

$$-\frac{9}{10}a^4-\frac{1}{10}a^3b+\frac{7}{60}a^2b^2+\frac{29}{25}ab^3-b^4$$

$$\frac{9}{10}a^4+\frac{1}{10}a^3b+\frac{7}{60}a^2b^2+\frac{29}{25}ab^3-b^4$$

$$\frac{9}{10}a^4-\frac{1}{10}a^3b+\frac{7}{60}a^2b^2+\frac{29}{25}ab^3-b^4$$

$$\frac{9}{10}a^4-\frac{1}{10}a^3b-\frac{7}{60}a^2b^2+\frac{29}{25}ab^3-b^4$$

$$x^2y^2-x^2z^2-2xyz^2+y^2z^2$$

$$x^2y^2-x^2z+2xyz^2-y^2z^2$$

$$x^2y^2-x^2z^2+2xyz^2-y^2z^2$$

$$\frac{5}{4}c^{5x+4}+\frac{3}{4}c^{5x+2}+\frac{1}{2}c^{5x-8}$$

$$-\frac{5}{4}c^{5x+4}+\frac{3}{4}c^{5x+2}+\frac{1}{2}c^{5x-8}$$

$$-\frac{5}{4}c^{5x+4}+\frac{3}{4}c^{5x+2}-\frac{1}{2}c^{3x-8}$$