<u>The surface area of the region he will paint is 900 sq.ft.</u>
<u>Step-by-step explanation:</u>
Cubical room measures - 15 ft
Chaz want to paint only the walls of room
Surface of painting region means Lateral surface area (excluding top and bottom)
Lateral surface area of cube =
⇒ 4 * 15 *15
⇒ 900 sq.ft
<u> The surface area of the region he will paint is 900 sq.ft.</u>
7.32a + 2.1(2.7 -18a)
7.32a + 5.67 - 37.8a (multiply 2.1 to 2.7 and 18a)
5.67 - 30.48a (combine 7.32a and -37.8a since they are like terms)