(1)△ABC如图所示,∵A(-2,-1),B(-5,0),C(-2,4),∴AC=4-(-1)=5,点B到AC的距离为-2-(-5)=3,∴△ABC的面积= 1 2 ×5×3= 15 2 ;(2)△A′B′C′如图所示.