F(x)......ur output = 19
19 = 2x^2 + 3x + 5
2x^2 + 3x + 5 - 19 = 0
2x^2 + 3x - 14 = 0
(2x + 7)(x - 2) = 0
2x + 7 = 0
2x = -7
x = -7/2
x - 2 = 0
x = 2
I believe there is 2 possible answers......x (ur input value) = -7/2 or 2
The greatest number he can spend on is $5 since he has $10 he will have $5 reamining.
Your multiplying 2 on the 4,8,16,32 one then adding 1 on the 1,2,3 one which could determine the rate of change
Lets write equation of a function:
y = kx + n
Direct variation in simple is equation of a line which has n=0 or in other words which y to x ratio is k.
First option gets 7=7 but it isnt direct variation because n is not equal to 0
third option is indeed correct. once we implement coordinates (2,7) we get 7=7
Answer is
y = 7/2x