Solution - Simplification or other simple results

Reformatting the input :

Changes made to your input should not affect the solution:

 (1): "y1"   was replaced by   "y^1". 

Step  1  :

Multiplying exponential expressions :

 1.1    y²⁸ multiplied by y¹⁵ = y^{(28 + 15)} = y⁴³

Final result :

  y43