a取何值时,代数式(a+1)^2+2(a-2)-2的值不小于0答案是(a+1)^2+2(a-2)-2》0a^2+4a-5》0(a-1)(a+5)》0所以a>1或a

Question

a取何值时,代数式(a+1)^2+2(a-2)-2的值不小于0
答案是 (a+1)^2+2(a-2)-2》0
a^2+4a-5》0
(a-1)(a+5)》0
所以a>1或a

Answer 1

,代数式
(a+1)^2+2(a-2)-2的值不小于0
即(a+1)^2+2(a-2)-2≥0
a^2+4a-5≥0
(a-1)(a+5)≥0
∴{a-1≥0 或{a-1≤0
{a+5≥0 {a+5≤0
==>
{a≥1 或{a≤1
{a≥-5 {a≤-5
==>a≥1 或 a≤-5