Hey I hope this helps you You first need to move everything to one side to equal zero. Then factor out the 5 After you should be left with a quadratic equation easier to work with What multiplies to 30 and adds to -11? This would be 6 and 5 But since it is -11 those two numbers need to be negative as well
Make on side 0 because if ab=0 then assume a and b=0
so first minus 11r from both sides
5r²-55r+120=-30 divide both sides by 5 for convenience r²-11r+24=-6 add 6 to both sides r²-11r+30=0 factor what 2 numbres multiply to get 30 and add to get -11 -6 and -5 (r-6)(r-5)=0 set each equal to 0