PLEASE HELP URGEN

A row operation is performed on a matrix as shown below.

I 2 -1 1 I 4 I. I 0 -3. x I -18 I
I 1 1 1 I 11 I > I 1. 1. 1 I 11 I
I 4. -2 2 I 5 I. I 4 -2 2 I 5 I

What is the value of x?
a. -2
b. -1
c. 0
d. 3

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:

the answer is b

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step-by-step explanation:

so mark-up is 0.4 multiplied by 180 = 72