34- 



-ALGEBRA. 



5. Given j , z __ r h to nnd ;v and y. 



yhe first analogy turned inXQ an equatioa 

 Is l;x:r:ayy qt x=z y, 

 And this value of x^ substituted in the second. 



Gives 2' 



+>''■='■' «■ -^+:»''='^> 



Or «'/+i'/=r^S or^*= -^, 



And therefore, y: 



cb 



a'+b' 



y and x: 



ca 



'+^ 



4. Given - — J-7_)=:?99j and -^^ — |-7.v = 5Lj to find Pf. 



end j,'. 



A ns. a; = 7, and j;^!: 1 4. 



c. Given 12= -^ +8, and —^ 4 r 8 = 



^ 2 ' 4 5 3 



ly — X 



4-273 to find X and y. Ans. k = 60, and y'=:=^^o. 



6. Given ^ : (^ : : »v : Vj and at ^ — -j^^zrij to find a; and ^v 



Ans. 



da^^ 



:.v, and 



^^^ 



'—h- 





RULE 3. 



Let the given equations be multiplied or divided by such 

 numbers or (|Uiintities, as will make the term, which con- 

 tains one of the unknown quantities, to be the same in 

 both equations j and tlien by adding or subtracting the 

 equations, according as is required, there will arise a new- 

 equation \vith only one unknown quantity, as before. 



EXAMPLES, 



