Please help me with my algebra.

(8, -1)

Step-by-step explanation:

To use elimination, we can add the two equations together to eliminate the y:

x-y = 9

x+y = 7

x + x -y + y = 16

2x = 16

x = 8

Plug that back into the original equation to get:

8-y = 9

y = -1

So the ordered pair is (8, -1)

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.

explanation:

infrared radiation has wavelength in the range between 700 nm and 1 mm. lets' convert these values into scientific notation, keeping in mind that:

let's start from the lower value, we have:

(we moved the dot two places to the left, so we increased the exponent by 2 units, from -9 to -7)

the higher value is:

so, the range of wavelength of infrared radiation is: