The equation a = startfraction one-half endfraction left-parenthesis b 1 plus b 1 right-parenthesis.(b1 + b2)h can be used to determine the area, a, of a trapezoid with height, h, and base lengths, b1 and b2. which are equivalent equations? check all that apply. startfraction 2 a over h endfraction minus b 2 equals b 1.– b2 = b1 startfraction a over 2 h endfraction minus b 2 equals b 1. – b2 = b1 startfraction 2 a minus b 2 over h endfraction equals b. = b1 startfraction 2 a over b 1 plus b 2 endfraction equals h. = h startfraction a over 2 left-parenthesis b 1 plus b 1 right-parenthesis endfraction equals h.= h