the points a ( 0 , 0 ) , b ( 0 , 4 a - 5 ) and c ( 2 a + 1 , 2 a + 4 ) form a triangle . if angle abc = 90 , what is the area of triangle abc ?
"1 / 2 bh = 1 / 2 ( 2 a + 1 ) ( 2 a + 4 ) now 4 a - 5 = 2 a + 4 2 a = 9 therefore , a ( 0,0 ) ; b ( 0,13 ) ; c ( 10,13 ) 1 / 2 * 10 * 13 = 65 answer : e"
divide(multiply(subtract(multiply(divide(add(4, 5), 5), 4), 5), add(multiply(divide(add(4, 5), 5), subtract(4, 5)), 1)), 5)