PP-T1-DS33

[max999]

If a > 0, b > 0, and c > 0, is a(b - c) = 0 ?

(1) b – c = c - b
(2) b/c = c/b

answer:d

[smilego]

If a > 0, b > 0, and c > 0, is a(b - c) = 0 ?

(1) b – c = c - b
(2) b/c = c/b


(1) 移過去就可以所得 b=c 充分
(2) b平方=c 平方
題目有說, b > 0 and c > 0 取正
所以 b=c 充分