Add (7х2 – 3x) + (5х – 6).
ОА. 7х2 + 8x - 6
Ов. 4х2 - x
Ос. 7х2 + 2х - 6
OD. 7х2 – 2х -

Option C: The solution is

Explanation:

The given expression is

We need to solution of the given expression.

The solution of the given expression can be determined by adding the two expressions.

Let us remove the parenthesis.

Thus, we have,

Adding the like terms, we have,

Thus, the solution is

Hence, Option C is the correct answer.

Part A)

Using the Pythagorean theorem you can find the height:

17^2 = 8^2 + x^2

289 = 64 +x^2

x^2 = 289 - 64

x^2 = 225

x = √225

x = 15

The height is 15 cm.

Part B)

Area of the triangular side: 1/2 x 16 x 15 = 120 square cm.

There are two triangles so 120 x 2 = 240 square cm.

One side = 20 x 17 = 340

There are 2 sides so 340 x 2 = 680 square cm.

The bottom is 16 x 20 = 320 square cm.

Total cardboard needed: 240 + 680 + 320 = 1,240 square cm.