Linda has 12 eggs left, 5 of which are brown, so 12 - 5 = <<12-5=7>>7 are white.
Linda originally had 3 times as many white eggs as brown eggs, or 3 * 5 = <<3*5=15>>15 white eggs.
So Linda broke 15 - 7 = <<15-7=8>>8 white eggs.
#### 8