Diego plans to build an extension to his rectangular model bridge. Let x represent the increase, in centimeters, of the model's length. The expression 2 1 (x + 8) represents the area of the model bridge, where 2 1 is the width, in centimeters, and (x + 8) represents the extended length, in centimeters, of the model. Which expression is equivalent to 2 1 (x + 8)?

(21x+168)cm²

Step-by-step explanation:

If the expression 2 1 (x + 8) represents the area of the model bridge, where 2 1 is the width, in centimeters, and (x + 8) represents the extended length, the expression that is equivalent to 21(x+8) can be gotten by expanding the function. The expansion of the function will give the area of the rectangular model bridge as shown;

21(x+8) = 21x+ 168

The expression equivalent to 21(x+8) is therefore (21x+68)cm²

Note that the the unit of the value and function given is in cm therefore the unit of their equivalent expression will be in cm²

21x + 168 cm

Step-by-step explanation:

According to the question, 21 ( x + 8) represents the area of the extended model bridge.

Since the model bridge is rectangular, the length is x + 8 cm while the width is 21 cm. Hence, the area of the rectangular model bridge will be 21 × (x + 8) using Length (L) × Breadth (B) formula.

21 × (x +8)

= 21 (x +8)

Opening the bracket, we will have:

21x + 168 cm.

21x + 168 is equivalent of 21 (x + 168) just that the former expression is an expanded form.

for this case we have that by definition, the volume of a cylinder is given by:

where:

r: it's the radio

h: it's the height

we have as data that:

substituting:

so, the cylinder volume is

option d