Question

初一数学题急已知(a+b)的2次方=7 （a-b)的2次方=3求a的4次方+b的4次方 已知x+y=-5 x3+y2=1

Answer 1

(a+b)(a+b)=7 (a-b)(a-b)=3 (a+b)(a+b)-(a-b)(a-b)=4ab=7-3=4 ab=4

(a+b)(a+b)+(a-b)(a-b)=2(a方+b方)=7+3=10 a方+b方=5

4 4 2 2

(a方+b方)方=a +b +2a b =5*5=25

4 4 2

a + b =25-2*(ab) =25-2*1=23