Question

find the values of x & y that maximize or minimize the objective function

4x+3y≥30
x+3y≥21
x≥0,y≥0

Minimum for C=5x=8y

Answer 1

graph both lines above :
4x+3y = 30 and
x + 3y = 21


to get the coordinat point B, do elimination and subtitution method to solve systems :
4x + 3y = 30
x + 3y = 21
------------ (-)
3x = 9
x = 9/3 = 3

x + 3y = 21
3 + 3y = 21
3y = 21 - 3
3y = 18
y = 6
so, point B is (3,6)