| 7.2 Simultaneous Equations Two or more equations (system of equations) that are true at the same time and are therefore satisfied by the same values of unknowns involved; are called simultaneous equations. The equations 2 x + y = 3 3x + 4y = 2 are simultaneous equations having solution x = 2, y = -1 Method of solving the simultaneous equations : 1. Method of substitution This method involves substituting one equation into another. Example Solve the equations x = 2 + y x + 2 y = 17 Solution: x = 2 + y . . . (1) x + 2 y = 17 . . . (2) From (1), Substitute (y + 2) for x in (2) ( y + 2) + 2 y = 17
3 y + 2 = 17 Transposing, 3 y = 15 \ y = 5
Now insert y = 5 in (1) x = 5 + 2 x = 7 \ x = 7 , y = 5 . . . Required solution
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7.1 Definition |