# Thread: what is the minimum value of a^2+6a-7

1. ## what is the minimum value of a^2+6a-7

what is the minimum value of a^2+6a-7

2. ## Re: what is the minimum value of a^2+6a-7

set it to zero and solve for a

3. ## Re: what is the minimum value of a^2+6a-7

Originally Posted by vegasgunner
what is the minimum value of a^2+6a-7
a=1 and a=7 so 1 is the answer

4. ## Re: what is the minimum value of a^2+6a-7

Originally Posted by haftakhan
a=1 and a=7 so 1 is the answer
oi. He didn't show any workings, so I don't think it's a good idea just to give an answer like that.

5. ## Re: what is the minimum value of a^2+6a-7

Originally Posted by LimpSpider
set it to zero and solve for a
No, you need to set the DERIVATIVE equal to 0 and solve for a. You also need to give an argument as to WHY it is a minimum.