Standard form or slope intercept form would be y=mx+b or
4/5y=9/10x +3/5 simplified
so to simplify divide both sides by 4/5.
(This would be easier to do if you converted the fractions to decimals)
0.8y=0.9x + 0.6 (divide both sides by 0.8)
y= 1.125x + 0.75
or
y= 9/8x + 3/4