McKenna was asked to write the following expression in standard form. 3-5(3a+6)3−5(3a+6)

When writing the expression in standard form, McKenna made a mistake.

Step 1 2(3a+6)
Step 2 -6a+(-12)
Step 3 -6a-12
Step}\ 4 3−5(3a+6)

3+(−5)(3a+6)

−2(3a+6)

−6a+(−12)

−6a−12

a. McKenna made her first mistake in Step 2

.

b. The correct expression in standard form is

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:

10 - 8 = -2

  8 - 6 = -2

etc, so -2 is the common difference

step-by-step explanation: