linear models onvolving simultaneous

i need help starting off

Anne and Maureen live in towns that are 57km apart. Anne sets out at 9.00pm one day to ride her bike to Maureen's town at a constant speed of 20km/h. At the same time Maureen sets out to ride Anne's town at a constant speed of 18km/h.

write down a rule for the distance,dkm, that each of them is from Anne's place at a time t minutes after 9.00pm

q2.the straight line with equation ax+by=c passes through the points (2,4) and (-3,1). find the values of a,b,c.
attempt
1-4/-3-2= 3/5
so y=3/5x +c
fiind c, (2,4)
4=(3/5*2) +c
c= (4-6/5)

so equation is y=3/5x + 14/5 ? but answer isnt correct , answer is a=-3 b=5 c=14
thanks

yumm said:

i need help starting off
Anne and Maureen live in towns that are 57km apart. Anne sets out at 9.00pm one day to ride her bike to Maureen's town at a constant speed of 20km/h. At the same time Maureen sets out to ride Anne's town at a constant speed of 18km/h.
write down a rule for the distance,dkm, that each of them is from Anne's place at a time t minutes after 9.00pm

Click to expand...

ONCE MORE yumm: speed = distance / time

So after t hours, Anne travelled 20t km, Maureen travelled 18t km

Carry on....

yumm said:

q2.the straight line with equation ax+by=c passes through the points (2,4) and (-3,1). find the values of a,b,c.
attempt
1-4/-3-2= 3/5 ****
so y=3/5x +c
fiind c, (2,4)
4=(3/5*2) +c
c= (4-6/5)
so equation is y=3/5x + 14/5 ? but answer isnt correct , answer is a=-3 b=5 c=14

Click to expand...

WHAT are you doing with: ax + by = c ??
by = -ax + c
y = (-a/b)x + c/b

Try again...

**** needs brackets: (1 - 4) / (-3 - 2)