A=(x^2+4x+4)+4=(x+2)^2+4=(8+2)^2+4=10^2+4=100+4=104
B=(6-x)^2=(6-16)^2=(-10)^2=100
C=(2x)^2-(7y)^2=(2x-7y)(2x+7y)=(-280-280)(-280+280)=(-280-280).0=0
D=3(x^2+4x+4)=3(x+2)^2=3(998+2)^2=3.1000^2=3.1000000=3000000

1)thay x = 8 vào A ta được A= 8^2 + 4.8 + 8 =  64+32+8 = 104
 

1) A = x^2 + 4x + 8 = 8^2 + 4.8 + 8 = 64 + 32 + 8 = 104
2) B = 36 - 12x + x^2 = (6 - x)^2 = (6 - 16)^2 = (-10)^2 = 100
3) C = 4.x^2 - 49.y^2 = (2x - 7y)(2x + 7y)
= (-280 - 280)(-280 + 280) = 0
4) D = 3.x^2 + 12x + 12 = 3(x^2 + 4x + 4)
= 3(x + 2)^2 = 3.(998 + 2)^2 = 3 . 1000^2
= 3 . 1000000 = 3000000