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Please Help solve simultaneous equations , I never got hang of it.

1. a+3b=5
3a+2b=8

2. 3m-4n= -14
2m+2n= 14


User Micmdk
by
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2 Answers

5 votes

Answer:

see explanation

Explanation:

(1)

a + 3b = 5 ( subtract 3b from both sides )

a = 5 - 3b → (1)

3a + 2b = 8 → (2)

Substitute a = 5 - 3b into (2)

3(5 - 3b) + 2b = 8 ← distribute and simplify left side

15 - 9b + 2b = 8

15 - 7b = 8 ( subtract 15 from both sides )

- 7b = - 7 ( divide both sides by - 7 )

b = 1

Substitute b = 1 into (1)

a = 5 - 3(1) = 5 - 3 = 2

Then a = 2 and b = 1

(2)

3m - 4n = - 14 → (1)

2m + 2n = 14 → (2)

Multiplying (2) by 2 and adding to (1) will eliminate the n- term

4m + 4n = 28 → (3)

Add (1) and (3) term by term to eliminate n

7m + 0 = 14

7m = 14 ( divide both sides by 7 )

m = 2

Substitute m = 2 into either of the 2 equations and solve for n

Substituting into (2)

2(2) + 2n = 14

4 + 2n = 14 ( subtract 4 from both sides )

2n = 10 ( divide both sides by 2 )

n = 5

Then m = 2 and n = 5

User Neat
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4 votes


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Please Help solve simultaneous equations , I never got hang of it. 1. a+3b=5 3a+2b-example-1
User Anatole Lucet
by
3.1k points