Answer:
19) x=10
21) x=2
Explanation:
19) you must first cross multiple giving you 15 = x+5 so solve for x you subtract 5 from both sides giving you x=10
21) You must cross multiply to give you 12x= 8(x+1), you then must distribute the 8 to give you 12x= 8x+8 then subtract 8x from both sides to give you 4x=8 and then you divide both sides by 4 to give you x=2