Answer:
To find the x-intercepts we can write:
0 = -1/2(x + 3)² + 4
0 = -1/2(x² + 6x + 9) + 4
0 = -1/2x² - 3x - 9/2 + 4
0 = -1/2x² - 3x - 1/2
0 = x² + 6x + 1
x = -3 ± 2√2 (use quadratic formula)
As a decimal this can be written as x = -5.83, x = -0.17.
