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3 years ago

— 3y — 4х = -11 3y — 5х = — 61

Mathematics

2 answers:

storchak [24]3 years ago

6 0

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shtirl [24]3 years ago

6 0

Answer:

x = 8

y = -7

Step-by-step explanation:

-3y - 4х = - 11 .................................... (1)

3y - 5х = - 61 ..................................... (2)

From equation (2),

3y = -61 + 5x

divide through by 3 to have 'y' as the subject

y = -61/3 + 5x/3 ........................ (3)

Substitute for 'y' in equation (1) to get 'x'

Putting equation (3) in equation (1)

-3 (-61/3 + 5x/3) - 4x = -11

Open the bracket first

61 + (-5x) - 4x = -11

61 - 5x - 4x = -11

61 - 9x = -11

collect like terms

61 + 11 = 9x

72 = 9x

divide through by 9

8 = x

∴ x = 8

Substitute for x in either of the above equation to get 'y'

Using equation (3)

y = -61/3 + 5(8)/3

simplify

y = -61/3 + 40/3

common denominator

y = (-61 +40) / 3

y = -21 / 3

y = -7

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