若(x2+y2)4-8(x2+y2)2+16=0,则x2+y2=______.
题型:填空题难度:简单来源:不详
若(x2+y2)4-8(x2+y2)2+16=0,则x2+y2=______. |
答案
∵(x2+y2)4-2×(x2+y2)2×4+42=0, ∴[(x2+y2)2-4]2=0, ∴x2+y2-4=0, ∴x2+y2=4. |
举一反三
因式分解: (1)8x2+12x; (2)x2-12x+36. |
下列分解因式正确的是( )A.x3-x=x(x-1)2 | B.x2+y2=(x+y)(x-y) | C.-x2-y2=-(x-y)(x+y) | D.4x2-4x+1=(2x-1)2 |
|
分解因式: ①x2+6x+9=______; ②1-4x+4y2=______; ③-a2+2a-1=______. |
最新试题
热门考点