Posted by Lucas on .
4r^2+21r=r+13
3s^226s+2=5s^2+1
Please, please could you be so nice and help me with step by step, I can't find right solution, Thank you so much!!!!

algebra 
Steve,
always set everything equal to zero. That way if you find factors, you knwo that each factor that is zero will provide a root.
4r^2 + 20r  13 = 0
use the quadratic formula to get
r = 5/2 ± √3
2s^2  26s + 1 = 0
s = 1/2 (13 ± 3√19)