I need help what’s 4a-4=8+a

Find the sum to the equation 3+6+9+

Find the balance at the end of 4 years if 1000 is deposited at the rate of

The radius of the circle is 4 cm and the measure of the central angle is 90° the area of the sector with a central angle measuring 90° and radius of length 4 cm is vt cm the triangle in the sector is 4 cm the area of the triangle is v/cm² the area of the segment of the circle is (471 - ) cm?