Solve the following simultaneous equations:

\[\frac{7}{2x + 1} + \frac{13}{y +2} = 27\] and \[\frac{13}{2x + 1} + \frac{7}{y + 2} = 33\]
Answer:

Let ,

\[\frac {1}{2x + 1}= m\] and \[\frac{1}{y + 2}= n\]
now, equations become,
7m + 13n = 27 ——–A
13m + 7n = 33 ——– B
adding A and B,

7m + 13n = 27

13m + 7n = 33


20m + 20n = 60

dividing above equation by 20 on both sides

now, m + n = 3 —————C

subtracting equation B from A

7m + 13n = 27

13m + 7n = 33


-6m + 6n = -6

Diving above equation by (-6 ) on both sides,

m – n = 1 ————-D

Solving equation C and D,

m + n = 3

m – n = 1


2m = 4

m =2

put m =2 in equation C,
m + n = 3
2 + n = 3
n = 3 – 2
n = 1
n = 1
we have
\[\frac {1}{2x + 1}= m\] \[\frac {1}{2x + 1}= 2\]

2(2x + 1) = 1

4x + 2 = 1

4x = 1-2

4x = -1

\[x= \frac{-1}{4}\]

we have,

\[\frac{1}{y + 2}= n\] \[\frac{1}{y + 2}= 1\]

y + 2= 1

y= 1 – 2

y = -1

Answer: \[x= \frac{-1}{4} and y= -1 \]

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