multiply rational algebraic expressions.

1) 3x^2/2y × 4y^3/3x
2) x + 7/7x + 35 × x^2 - 3x - 4/x - 8
3) 2x/x-3 × x-3/5x^2
4) 13x/10z × 2x/5z
5) 9x^2/x^2 + 12x + 36 × x^2 + 6x/12x​