If 2x+1 is a factor of 2x³ +x²-kx-1, find the value of k

A. 90 degrees b. 45 degrees c. 30 degrees d. 120 degrees

Which number line correctly shows 0.8 + 0.3?

Solve these problems: 1.what is the perimeter of an equilateral triangle with sides measuring 6cm? 2. a regular pentagon has sides measuring 3.2 cm. what is its perimeter? 3. a regular decagon has sides of 3.5mm . what is it’s perimeter? 4. a regular octagon has a perimeter of 64cm. what is the length of one of the sides? 5. a regular hexagon has a perimeter of 72mm . what is the length of one of the sides? 6. what is the perimeter of a rhombus with sides measuring 11m?