To know the value of the y we have to clear it as follow:
[tex]y-60=-6(x-15)[/tex]First we make the opperation - 6 (x - 15)
[tex]-6(x-15)=-6x-(-6\cdot15)=-6x+90[/tex]Then we have:
[tex]y-60=-6x+90[/tex]Now we add 60 in each side of the equation:
[tex]y-60+60=-6x+90+60[/tex]We make the addition:
[tex]y-0=-6x+150[/tex]We simplify:
[tex]y=-6x+150[/tex]