We need the rates please attach a picture
If you expand the square, you have

Simplify the right hand side:

Cancel the -3x appearing on both sides:

Multiply both sides by 4:

Consider the square root of both terms (using the doubles sign):

Answer:
I just want points hahahaha
$1235-$800=$435 thus the I which is the simple interest
:I=PRT all over 100
435=800(R) (5)all over 100
43500=4000R
:R=10.88%