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27 votes
27 votes
Solve the simultaneous equations
Show clear algebraic working.
7x+2y=5.5
3x-5y=17

User Walter Cameron
by
3.0k points

1 Answer

16 votes
16 votes

Answer:

(1.5, - 2.5 )

Explanation:

7x + 2y = 5.5 → (1)

3x - 5y = 17 → (2)

multiplying (1) by 5 and (2) by 2 and adding will eliminate y

35x + 10y = 27.5 → (3)

6x - 10y = 34 → (4)

add (3) and (4) term by term to eliminate y

41x + 0 = 61.5

41x = 61.5 ( divide both sides by 41 )

x = 1.5

substitute x = 1.5 into either of the 2 equations and solve for y

substituting into (1)

7(1.5) + 2y = 5.5

10.5 + 2y = 5.5 ( subtract 10.5 from both sides )

2y = - 5 ( divide both sides by 2 )

y = - 2.5

solution is (1.5, - 2.5 )

User Niko Lang
by
3.2k points