Answer:
600
Step-by-step explanation:

x max = 
a = -5
b = 6
-6/2(-5) = 6/10 = 3/5 = .6
.6 thousand = 600
600 speakers should be sold.
Alternatively, you can check the vertex of the parabola formed.
Doug is 5 years old.
5 + 3 = 8
5 × 8 = 40
<span>2x + 4y = 36
3x - 4y = -6
--------------add
5x = 30
x = 6
</span>2x+4y=36
2(6)+4y=36
12 + 4y = 36
4y = 24
y = 6
answer
<span>(6, 6) is a solution of equations
</span><span>(4,7) is NOT a solution of equations</span>
Answer:
1 8/25
Step-by-step explanation: its right