Math

115

- Notes

I"esscx#Z

Solving

a system

of

equations

by Substitution

(1)

p=98 -{317)q

(2)

p:

(sl3)

q-

342

substitute

the

expression

for

p

into

equation

(2)

to

eliminate

p

98

-

(3/7)

q:

(5/3)

q-

342

clear

all

fractions

by

multiplying

both

sides

by

the LCD

of all denominators

LCD of7

and

3

=

2l

(21)

tes

-

(3t7)

ql

:

(21)

t

(s/3) q.342)

2058

-

9q.: 35q

-

7182

924A

=

Mq

210=q

substitute

this

value

for

q

into

either

(1)

or

(2)-

Let's choose

(l)

P

:98

-

(317)

{210)

=98

-90:8

solution:

p:8,

q:210