Sometimes zero pairs must be added to close the rectangle. Adding zero pairs does not change the value of the original expression since they, like their name implies, equate to 0. For example, if you need to add an x tile, you MUST also add a -x tile to keep the balance of the expression. Factor
with algebra tiles.

Pls help :)​

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:

b