If if x+y=10, find the value of y when x=3

The answer is 7.2 how would you put this as money

David pays a 20% income tax on his $2,100 salary. how many dollars is the tax? show work

Asystem of equations is given below.y= 1/2x-3 and y=-1/2 x-3which of the following statements best describes the two lines? a.they have the same slope but different y-intercepts, so they have no solution.b.they have the same slope but different y-intercepts, so they have one solution.c.they have different slopes but the same y-intercept, so they have no solution.d.they have different slopes but the same y-intercept, so they have one solution.html