Please help me with this math question

4 is always true

Step-by-step explanation:

I'm not sure if there's a faster way to do this, but you can randomly substitute numbers in and eliminate choices.

One and two can be immediately eliminated, because x can be any number and there are no squares, exponents, etc. If there were a x² and +9 it will always be a positive number (negative number squared will always be positive), but in this case there isn't.

Since there is a +9, we know that if x is a positive number f(x) will always be postitive. For statement 3 however, if you substitute a negative number that is too "small" for example -3, you get -1+9 which is 8. This doesn't fufill the requirement of "If x < 0 then f(x) < 0".

answer: the price of one pound cabbage = $ 0.8

the point (10,8) represents that the cost of 10 pounds cabbage is $ 8

step-by-step explanation:

since, here is a proportional relation between the number of pounds of cabbage (x) and the price in dollars (y).

therefore, we can write,

⇒ y = k x

where k is the constant of proportionality.

now, point (5,4) is in the line.

thus, it will satisfies the above equation of line.

⇒ 4 = 5 k

⇒ k = 0.8

thus, the equation of the line is,

y = 0.8 x

a) for x = 1,

y = 0.8

therefore, the cost of one pound of cabbage is 0.8 dollars.

b) in the below graph (10,8) represents that the cost of 10 pounds of cabbage is 8 dollars.