Three friends, Nakobe, Mikah, and Ashton, are saving up money to buy microphones for their podcast. The total cost of the microphones is represented by the expression 9x2 3x + 4. The friends have already saved the following amounts: Nakobe: x2 Mikah: x 12 Ashton: 3x + 4 Which expression represents the amount of money the friends still need to buy the microphones? 8x2 7x 4 8x2 7x + 12 4x2 + 5x + 4 x2 + 4x 8