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The sum of two numbers is 47. twice the first number and three times the second number have a sum of 100. Set up a system of equations to find the numbers

2 Answers

5 votes

x + y = 47

2x + 3y = 100

Solving steps

x + y = 47 (-2)

2x + 3y = 100

We multiply the first equation by -2. This is so that x changes to -2x (So it would match the x below). We can then cross it over, since the equation below has 2x and -2x + 2x = 0.

-2x - 2y = -94

2x + 3y = 100

Y = 6

We get y = 6 by subtracting -2y (From the above equation) from 3y. This gives us Y. Afterwards, We subtract -94 (From the above equation) from 100 and that gives us 6. Therefore, y = 6.

To get x. We sub in the value for y into one of the equations and solve.

2x + 3(6) = 100

2x + 18 = 100

We bring over 18 from one side to the other, to get x alone. We have to change 18 to - 18 because it crosses over to the other side.

2x = 100 - 18

2x = 72

x = 72÷2

x = 36.

X = 36

Y = 6

(36, 6)

User Magnus Melwin
by
4.1k points
12 votes

Answer:

23

Explanation:

User Worrawut
by
4.6k points