PLS HELP! 4. y= x-5, domain = {positive numbers}

6. y= 5/x, domain = {x:0.4 is less than or equal to, x, is less than or equal to, 10}

8. y= -0.4x+5, domain = {x: -2 is less than or equal to, x, is less than or equal to, 6}

12. y=-x^2+5.4x+1, domain = {positive numbers}

Teacher assigned multiple questions from Paul a. Foersters algebra and trigonometry book, but also didnt go into detail on how to solve these