2. (the square root of 5+26) × (the square root of 5-26) = 1 radical sign 1= plus or minus 1, so the term in the equal proportion is plus or minus 1.
3. let m=n, that is, 4x 2+x+ 1 = 3x 2+x = > X has no solution, so c and d are wrong.
Considering the respective symmetry axes of two parabolas (-b/2a), the minimum value of m is1516, and the minimum value of n is-112, so m >: n.
4. Let x=y=0 (that is, substitute the origin coordinates). If the inequality holds, the region contains the origin, obviously only the b term holds.
5. transposition: x 2-2x
6. M2+N2 = (m+n) 2-2mn = (m+n) 2-100 ≥ (twice root number (m=n=)) 2- 100 = (2 root number 50) 2-65438.
7.x+y≥2 Radical (xy)=2 Radical 4=4 If and only if x=y= Radical 4=2, take an equal sign (because X, y>0, x=y=-2).
Typing is very tiring ~ ~ ~