AC and BD are perpendicular bisectors of each other find the perimeter of ADB

Amerchant has coffee worth $60 a pound that she wishes to mix with 50 pounds of coffee worth $90 a pound to get a mixture that she will sell for $70 a pound. how many pounds of the & 60 coffee should be used?

Aflower has 26 chromosomes. to create a new flower,how many would a sperm cell have what is called?

Does anyone know how to solve and graph this: 4 + | a + 2 | < 7the only part i don't get is the "4 +"