
Patrick B. answered 10/25/20
Math and computer tutor/teacher
It is given:
x-y = 15
2x+8 < 3y <-- adding 8 to twice the larger is less
than 3 times the smaller
the first equation says: x-y-15=0
solving for y : y = x-15 <--- please label this equation ALPHA
solving for x : x = y+15 <--- please label this equaiton BETA
plugs ALPHA into inequality
2x+8 < 3(x-15)
2x+8 < 3x-45
8 < x-45
53 < x
so x>53 <-- please label this inequality GAMMA
solves the original inequality for y:
2x+8 < 3y
2x < 3y -8
x < (3y-8)/2
plugs in eqaution BETA:
y+15 < (3y-8)/2
2y +30 < 3y-8
30 < y-8
38<y
So y>38 <--- please label this inequality DELTA
THerefore:
x>53, y>38, and x-y=15 <-- combines inequalities GAMMA and DELTA
check:
let x=55 and y=40 so that x-y=15
then 2(55)+8 = 118 while 3y = 120
and the inequality does hold