SIMPLE EQIJATI0N6. 34 I 



4. Given ij^-j-,vz^34, an4 4v-|-A'Zi:i6 ; to find x and r. 



Ans. a;-z:8, and jzra. 



J. Given - +^ =J'-. =^'"1 7 -h j = T-^ -. to ^"'1 

 ft; and J. Ads. :>':=:-, and jrzzvv 



Y 6. Given *v-4-;z:;:/, and .v*-- — -j'* :z:zd *, to find »v and y. 



Ans. A'^ 5 and v^::: . 



2s '. IS 



RULE 2. 



1. Consider which of the unknown quantities you would 

 iirst exterminate, and let it$ value be found in that equa- 

 tion, where it is least ixxvolved. 



2. Substitute the value thus found for its equal in the 

 Other equation, and there will arise a new equation v/icji 

 Qiily one unknown q[uantity, whpse value may be found as 

 before. 



ex;a?v1ples, 



1. Given \ '■ "r^^~- -^7 I fQ £j^jj ^ ^^ 



From the first equation A-nz 1 7 — 2r, 

 And this value, substituted for a' in the second, gives 



17 ^J^-XS ^,V~2, 



Or 51 — 6;—;— 2, or 5 1 — -jy^iz y 

 That is, 7j'=5i — 2=^=49 ; 

 Whence y^""-^—^, and a:—!;- — 2j-— 17 — 14-^3. 



2. Given < "n'—^H ( ^q r^^^^ ^ ^^^ 



lx—y~ 2>S 

 From the first equation >:^ 13 — y. 

 And this value, being substituted for pc in the sccaiid, 

 Gives i3«— j--y=:3^ or 13 — 2;'=:3 ; 

 That is,: 2jj;= 13 — 3= 10, 

 Or ;y= V=S> and ;v=:i3—)':^i 3—5=^ 8. 



3. G:vca 



