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Pls help me with this​

Pls help me with this​-example-1
User Cwiggo
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1 Answer

28 votes
28 votes

Explanation:

let's just write the equations on top of each other as in a large subtraction, then transform one of them so that at least one term is the range in both equations, and then do the subtraction.

a)

I automatically write rational numbers as the total fractions (14 1/4 = 57/4, 3 3/4 = 15/4)

15x - 7y = 57/4

- 5x - y = 15/4

15x - 7y = 57/4

- 15x - 3y = 45/4

-------------------------

0 -4y = 12/4

y = -(12/4)/4 = -12/16 = -3/4

then we use that in the simpler second equation

5x - -3/4 = 15/4

5x + 3/4 = 15/4

5x = 12/4

x = (12/4)/5 = 12/20 = 3/5

b)

we don't need to transform any equation, as the x terms are already equal.

3x - 4y = 2

- 3x - 7y = -1

-------------------

0 3y = 3

y = 3/3 = 1

using this in e.g. the first equation

3x - 4×1 = 2

3x - 4 = 2

3x = 6

x = 6/3 = 2

User Jossie Calderon
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