x+y=90 x=smaller number y=larger number 2y+50= 20+3x (if 20 is added to 3 times the smaller number, the result exceeds twice the larger by 50. find the number.) x=90-y (isolate x, so you can substitute) 2y+50=20+3(90-y) - (substitution) 2y+50=20+270-3y ( distributive property) 5y+50=20+270 ( add 3y to both sides) 5y+50=290 ( added 20+270) 5y=240 ( subtract 50 from both sides) y=48 ( divide both sides by 5)
