I need help with the 3 highlighted questions below.

Question

Answer 1

x^2 +4x -5 = 0

(x+5)(x-1) = 0

x intercepts are x=-5 and x =1

y intercept is -5

x^2 + 4x + 4 = 5 +4 = 9 after completing the square

(x+2)^2 -9 = 0 in vertex form (x-h)^2 + k where (h,k) is the vertex

vertex is (2,-9), axis of symmetry is x = 2

-2x^2 -10 = 0

-2(x^2 -5) = 0

-2(x^2 - 5/2)^2 = 25/4

vertex = (5/2, -25/4) axis of symmetry is x=5/2

It's a downward opening parabola

-2x^2 -10=0

no real solution, no x intercepts

y intercept is y=-10 or the point (0,-10)