Problema Solution

Two times a number plus three times another number equals four. Three times the first number plus four times the other number is seven. Find the numbers.

Answer provided by our tutors

Two times a number plus three times another number equals four. Three times the first number plus four times the other number is seven. Find the numbers.

2x + 3y = 4

3x + 4y =7

from top equation:  2x =4 - 3y   so   x= 2- 3y/2

substitute for x into bottom equation:

3(2- 3y/2) + 4y =7

solve for y:

6 - 9y/2 + 4y=7

4y -4.5y = 1

-.5y=1

y= - 2

x= 2- 3(-2)/2 = 2+3=5

solution is x = 5 and y = -2

Check:

2x + 3y = 4

2(5) + 3(-2) = 4

10 -6=4

4=4

and

3x + 4y =7

3(5) + 4(-2)=7

15 -8=7

7=7