已知y=1⼀2x^2+2x-1,求: (1)当x取何值时,y=-3? (2)当x取何值时,y=5?

2025-04-27 05:35:08
推荐回答(2个)
回答1:

y=-3
1/2x²+2x-1=-3
两边乘2
x²+4x+4=0
(x+2)²=0
x+2=0
x=-2

y=5
1/2x²+2x-1=5
两边乘2
x²+4x-12=0
(x+6)(x-2)=0
x=-6,x=2

回答2:

Y=3.X=4
Y=5,X=8