Subtract

(3x^4+7x^3-9) - (5x^2-8x+4) =

3x^4 + 7x^3 - 5x^2 + 8x - 13

Step-by-step explanation:

(3x^4 + 7x^3 - 9) - (5x^2 - 8x + 4) =

The negative sign to the left of the second set of parentheses changes every sign inside the parentheses.

The first set of parentheses is unnecessary, so we just drop it.

= 3x^4 + 7x^3 - 9 - 5x^2 + 8x - 4

Now we combine like terms.

= 3x^4 + 7x^3 - 5x^2 + 8x - 13

answer: first option i.e. 'a' is correct.

step-by-step explanation:

since we have given that

number of minutes to wrap a small gift box = 4 minutes

we need to find the number of gifts to be wrapped in 5 minutes

since there is a direct variation, as the number of minutes will increase with   number of gifts to be wrapped.

so, let the number of gifts to be wrapped in 5 minutes be x.

so, it becomes,

hence, first option 'a'   is correct.

[2, 2.5)

(2.5, 3]

step-by-step explanation:

i think its these two not sure [2, 2.5)

(2.5, 3]