Rewrite the following quadratic function in vertex form. Then, determine the axis of symmetry. y=5x^2+15x-2

5x^2+15x-2
5(x^2+3x)-2
5(x^2+3x+2.25-2.25)-2
5(x^2+3x+2.25)-13.25
5(x+1.5)^2-13.25

final answer: y=5(x+1.5)^2-13.25
axis of symmetry: (1.5, 13.25)