Which expression has a value of 4 a: (21- 3) x (7 + 4) or b: 21 - 3 x 7 + 4 or (14 divided by 2) x 3 + 4 or c: 3 x 7 -14 + 4

its 69.420

step-by-step explanation:

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:

need more detail

step-by-step explanation:

lele