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28 votes
three times the first number plus seven times the second number equals 95. Four times the first number minus eleven times the second number equals 25. Find the two numbers

User Kayvan Karim
by
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1 Answer

16 votes
16 votes

The two numbers are 20 and 5

Step-by-step explanation:

let the first number = x

let the second number = y

three times the first number plus seven times the second number equals 95.

3(x) + 7 (y) = 95

3x + 7y = 95 ...(1)

four times the first number minus eleven times the second number equals 25

4(x) - 11(y) = 25

4x - 11y = 25 ...(2)

Combinig both equations:

3x + 7y = 95 ...(1)

4x - 11y = 25 ...(2)

Using elimination method:

multiply equation 1 by 4

multiply equation 2 by 3

The new equations:

12x + 28y = 380 .....(1)

12x - 33y = 75 ........(2)

subtract (2) from (1):

12x - 12x + 28y - (-33y) = 380 - 75

28y + 33y = 305

61y = 305

y = 305/61

y = 5

substitite for y in any of the equation:

Using equation (1): 12x + 28y = 380

12x + 28(5) = 380

12x + 140 = 380

12x = 380 - 140

12x = 240

divide both sides by 12:

x = 240/12

x = 20

The two numbers are 20 and 5

User PenthousePauper
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