A:x+y+3='0'
B:2x-y-5='0'
C:3x-y-9='0'
D:4x-3y+7=0
12+1 = 1×(2−1)(2+1)(2−1) = 2 ﹣1;
13+2 = 1×(3−2)(3+2)(3−2) = 3 ﹣ 2 ;
15+2 = 1×(5−2)(5+2)(5−2) = 5 ﹣2.
试求:
下列景观图位于黄土高原的是( )
把多项式4a3﹣8a2b+4ab2分解因式,结果正确的是( )