0.64x^2 - 225 + 0.36x^2 = 1x^2 - 225
9 - 4b^2 = 5b^2
2x^2 - (x^2 - 1) = 2x^2 - x^2 + 1 = x^2 + 1
9a^2 - 1 - 17a^2 = -8a^2 - 1
100x^2 - (20x + 16) = 100x^2 - 20x - 16
6x^2 - (x^2 - 0.25) = 6x^2 - x^2 + 0.25 = 5x^2 + 0.25
0.64x^2 - 225 + 0.36x^2 = 1x^2 - 225
9 - 4b^2 = 5b^2
2x^2 - (x^2 - 1) = 2x^2 - x^2 + 1 = x^2 + 1
9a^2 - 1 - 17a^2 = -8a^2 - 1
100x^2 - (20x + 16) = 100x^2 - 20x - 16
6x^2 - (x^2 - 0.25) = 6x^2 - x^2 + 0.25 = 5x^2 + 0.25