How do you solve (200/r)-1= 200/(r-10)(200r)1=200r10?

1 Answer
Apr 5, 2018

r = 5 +- sqrt(-7900)/2r=5±79002

Explanation:

200/r - 1 = 200/(r - 10)200r1=200r10

Rearrange the equation

200/r - 200/(r - 10) = 1200r200r10=1

Take 200200 common

200[1/r - 1/(r - 10)] = 1200[1r1r10]=1

Bring 200200 to other side

1/r - 1/(r - 10) = 1/2001r1r10=1200

Make denominators equal

(1/r × (r - 10)/(r - 10)) - (1/(r - 10) xx r/r) = 1/200(1r×r10r10)(1r10×rr)=1200

(r - 10)/(r(r - 10)) - r/(r(r - 10)) = 1/200r10r(r10)rr(r10)=1200

Now, denominators are same. Numerators can be added

(r - 10 - r) / (r(r - 10)) = 1/200r10rr(r10)=1200

(-10)/(r(r - 10)) = 1/20010r(r10)=1200

r(r - 10) = -2000r(r10)=2000

r^2 - 10r = -2000r210r=2000

r^2 - 10r + 2000 = 0 color(white)(.)……[1]r210r+2000=0.[1]

Use quadratic equation formula to find value(s) of rr

r = (-b +- sqrt(b^2 - 4ac))/(2a)r=b±b24ac2a

In equation [1][1]

  • a = 1a=1

  • b = -10b=10

  • c = 2000c=2000

r = (-(-10) +- sqrt((-10)^2 - (4 × 1 × 2000)))/(2 × 1)r=(10)±(10)2(4×1×2000)2×1

r = (10 +- sqrt(100 - 8000))/2r=10±10080002

r = (10+- sqrt(-7900))/2r=10±79002

r = 5 +-sqrt(-7900)/2r=5±79002