a+b=3 ab=-12①求a^2 +b^2②求(a-b)^2已知x-2y=15 xy=-25 求x^2 +4y^2-1已知x-y=5 (x+y)^2=49 求x^2 +y^2

来源：学生作业帮助网编辑：作业帮时间：2024/05/03 06:42:26

a+b=3 ab=-12①求a^2 +b^2②求(a-b)^2已知x-2y=15 xy=-25 求x^2 +4y^2-1已知x-y=5 (x+y)^2=49 求x^2 +y^2
a+b=3 ab=-12
①求a^2 +b^2
②求(a-b)^2
已知x-2y=15 xy=-25 求x^2 +4y^2-1
已知x-y=5 (x+y)^2=49 求x^2 +y^2

a+b=3 ab=-12①求a^2 +b^2②求(a-b)^2已知x-2y=15 xy=-25 求x^2 +4y^2-1已知x-y=5 (x+y)^2=49 求x^2 +y^2
a^2+b^2=(a+b)^2-4ab=9-(-24)=33
(a-b)^2 =a^2+b^2-2ab=33+24=57
x^2 +4y^2-1=(x-2Y)^2-4xy-1=225+100-1=324
x-y=5 (x+y)^2=49 求x^2 +y^2
x^2 +y^2 =(x+y)^2+(x-y)^2/2=37

a^2 +b^2=(a+b)^2-2ab=33
(a-b)^2=(a+b)^2-4ab=57
x^2 +4y^2-1=(x-2y)^2+4xy-1=624-20/3
x^2 +y^2=((x-y)^2+(x+y)^2)/2=37

1) a^2+b^2=(a+b)^2-2ab=3^2-(-12)*2=33
2) (a-b)^2=a^2+b^2-2ab=33-2*(-12)=57
x^2 +4y^2-1 =(x-2y)^2+4xy-1=15^2-4*25-1=124
4xy=(x+y)^2-(x-y)^2=24
2xy=12
x^2+y^2=(x+y)^2-2xy=49-12=37

a^2 +b^2=(a+b)^2-2ab=3^2+2*12=33;
(a-b)^2=(a+b)^2-4ab=3^2+4*12=57;
x^2 +4y^2-1=(x-2y)^2+4xy-1=15^2-4*25-1;
x^2 +y^2 =1/2[(x+y)^2+(x-y)^2]=1/2(49+25) .

已知3a*a+ab-2b*b=0(a不等于0,b不等于0),求a/b-b/a-(a*a+b*b)/ab的值. ab=-2 a+b=3 求ab(a²+b²)-a-b b/a+a/b=3,求2ab/(a*a+b*b)-(3a*a+ab+3b*b)/2ab的值已知a*a-ab=3,ab+b*b=-5,求代数式a*a+b*b与a*a-2ab-b*b的值已知a,b满足a+b=5,a-b=1,求ab,a^2+b^2-3ab 若a/b+b/a=3,求a^2+ab+b^2/a^2-ab+b^2的值已知a+b=12,ab=20,求a(a+b)(a-b)-a(a+b)^2的值已知a+b=12,ab=20,求a(a+b)(a-b)-a(a+b)^2的值 (a-b)(a^2+b^2+ab)/3-a^2b+ab^2=(a-b)^2,且a不等于b求a-b的值若a+b=3 ab=-2,求a+ab+ab+b的值已知a+b=2/3,ab=-2,求①(a-b)^2、②求a^3b-2a^2b^2+ab^3的值. 已知a+b=5,ab=-3,求2a+2b-3ab分求（2a-3b-2ab)-(a-4b-ab) 急若ab不等于0,且3a=b,求代数式b/3a-(-b)/a-a/2b/(-b) 已知a-b=5,ab=-4,求代数式5a^2b(a-b)-3ab(b-a)^2+5ab^2(b-a)的值已知a-b=5,ab=-4,求代数式5a^2b(a-b)-3ab(b-a)^2+5ab^2(b-a)的值已知a-b=5,ab=-4,求代数式5a^2b(a-b)-3ab(b-a)^2+5ab^2(b-a)的值若a/b=2,求分式a*a+ab-b*b/a*a-2ab+2b*b 已知a+2b=0,求a*a+2ab-b*b/2a*a+ab+b*b