[كاتـم الأسـرار]

( 1 ) 2a(3+2a)+4(2a-3)-2a(4-5a) = 6a+4a+8a-12-8a-7a = 3a-12 = ( 2 ) x-2y)2 + 2(2x+y)2) = x2 -4y2 + 8x2 + 2y2 = 9x2 - 8y2 =