Since you were able to type that negative, I will assume that
f(x)=-x^2+3x+8
the vertex is where the graph changes from increasing to decreasing or vice verca
find theh vertex
-b/2a is x coordinate of vertex where
f(x)=ax^2+bx+c
a=-1
b=3
-3/2(-1)=-3/-2=3/2
we see that the leading coeficient (a) is negative so the graph opens down
it increases then decreases at the vertex
so from negative infinity to 3/2 is interval
in interval nottaion
(⁻∞,3/2]
Perimeter =the length of border of a shape .....if its an equilateral triangle and one side is 32 then. Perimeter is three times the side.ie. 3x32=96cm
Cost of month plan = $40
Cost of minutes used = $0.45 after 700 minutes
Total cost = $48.10
Let x be the total minutes used
Total cost = 40 + 0.45(x - 700)
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Form the equation and solve x
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40 + 0.45(x - 700) = 48.10
40 + 0.45x - 315 = 48.10
0.45x - 275 = 48.10
0.45x = 48.10 + 275
0.45x = 323.10
x = 323.10 ÷ 0.45
x = 718
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Answer: John had used 718 mins this month
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OK dose solve for x we n33d to get x by its self so 42/7 is 6 x is 6
