Question

Hi I need to write these systems of equalities in slope intercept form so I can graph them. 20x+4.5y<=60 and 12x+20y<=60.
y=4 4/9x+ 13 1/3 (I think this is wrong)
y=-3/5x+3

Answer 1

Does your teacher insist that you have the relations in slope y-intercept form?

I will show you an easy way to sketch a graph if they are written in the form
ax + by = c

e.g. your 12x + 20y ≤ 60 or the boundary 12x + 20y = 60

put your pinkie finger over the x term (you let x=0)
what you see is 20y = 60
so in your head , y = 3 ---> the point (0,3), the x-intercept

now put your pinkie finger over the y term (you let y = 0)
what you see is 12x=60
so in your head , x = 5 ---> the point (5,0)

so now you have 2 simple points to graph your boundary.


do the same thing for the first one,
you might want to use your calculator for
4.5y = 60
y = 13 1/3

btw, your equations in the slope y-intercept form should have been
y ≤ - (4 4/9)x + 13 1/3
last one is right