Thread: A few problems I can't work out!

q/t=q/p+1 Express p in terms of q & t
(I'm using / as a fraction thing)

Solve 2 over x-1 minus 3 over x+1 equals 1 over 15

(12-2x)(10-2x)=80
Find the value of x

Thanks for any help, I'll probably need more

(1)

finally i get

(2)
Try equating the denominator first

After that cross multiply and solve for x ..


(3)
some expansion is required here

Can u continue from here ?

Thanks very much. Is it a quadratic equation I need to work out for the last one?

Originally Posted by mathaddict

(1)

finally i get

Em where does the -1 go?

Originally Posted by 1488ID

Thanks very much. Is it a quadratic equation I need to work out for the last one?

Yes .

Originally Posted by 1488ID

Em where does the -1 go?

note that

Originally Posted by mathaddict

note that

What mathsaddict has done is made 1 into and then solved from there

2 - 3 =
x-1 x+1

cross multiplying

2(x+1) – 3(x-1) = 1
(x-1)(x+1) 15

15(5-x) = x2 – 1
X2 + 15x- 76=0
Factorising
X2+4x+19x-76=0
Becomes
X(x+4)-19(x+4) = 0
Therefore x= -4 and 19

Originally Posted by correct

2 - 3 =
x-1 x+1

cross multiplying

2(x+1) – 3(x-1) = 1
(x-1)(x+1) 15

15(5-x) = x2 – 1
X2 + 15x- 76=0
Factorising
X2+4x+19x-76=0
Becomes
X(x+4)-19(x+4) = 0
Therefore x= -4 and 19

Correct