firat we need to get two equation with two varibles let us work on x,y
so adding the first and last one will yield
now we since we used the first and third we need to use the second to get a correct system.let us multiply the third by 2 then add the second and third
now we have two equation with the variables x and y
you can solve it algebraically but you can see that the only solution possible is y=0 and x=-1 we have the values for x and y let us choose one of the three main equation and substitute to get z let us pick the first equation 5x-2y+z=-1-->5(-1)-2(0)+z=-1---->-5+z=-1-------->z=4
to make sure the system works let us check by substituting into the three equations
the first one will be 5x-2y+z=-1--->5(-1)-2(0)+4=-1---->-5+4=-1--->-1=-1 first equation holds
the second equation 3x+y+2z=6---->2(-1)+0+2(4)=6--->-2+8=-6--->-6=-6 second equation holds
the third equation x-3y-z=-5----->-1-3(0)-4=-5---->-1-4=-5--->-5=-5
our third equation also holds which makes our solution correct
x=-1,y=0,z=4
Answer:
maybe it meane 11/a
Step-by-step explanation:
First, you have to find how many minutes he ran which would be 182 minutes. Then, to find out how many minutes he spent running each mile, you divide by 26. 182/26=7. 7 minutes per mile.
Two workers finished a job in 7.5 days.
How long would it take each worker to do the job by himself if one of the workers needs 8 more days to finish the job than the other worker?
let t = time required by one worker to complete the job alone
then
(t+8) = time required by the other worker (shirker)
let the completed job = 1
A typical shared work equation
7.5%2Ft + 7.5%2F%28%28t%2B8%29%29 = 1
multiply by t(t+8), cancel the denominators, and you have
7.5(t+8) + 7.5t = t(t+8)
7.5t + 60 + 7.5t = t^2 + 8t
15t + 60 = t^2 + 8t
form a quadratic equation on the right
0 = t^2 + 8t - 15t - 60
t^2 - 7t - 60 = 0
Factor easily to
(t-12) (t+5) = 0
the positive solution is all we want here
t = 12 days, the first guy working alone
then
the shirker would struggle thru the job in 20 days.
