SOLUTION: the sum of two numbers in 9. the difference between five times of the first and four times of the second is 9. what are that numbers?

Question 95: the sum of two numbers in 9. the difference between five times of the first and four times of the second is 9. what are that numbers?
Answer by terrtwo(10) (Show Source): You can put this solution on YOUR website!
translates Algebraically into:
x + y = 9 AND 5x - 4y = 9.
Solving the first eqaution for y, y = 9 - x.
Then substituting the first equation into the second:
5x - 4(9 - x) = 9 --> 5x - 36 + 4x = 9 --> 9x - 36 = 9.
Adding 36 to both sides --> 9x -36 + 36 = 9 + 36 --> 9x = 45.
Divide both sides by 9 --> 9x/9 = 45/9 --> x = 5.
Not finished yet since we still must go back to find y by subsititing the known value of x into either of the orginal equations --> 5 + y = 9
Substact 5 from both sides --> 5 + y - 5 = 9 - 5 --> y = 4
Therefore x = 5, y = 4
RELATED QUESTIONS
the sum of two number in 9.yhe difference between five times of the first and four... (answered by checkley79)

The Sum of two numbers is 9 . the difference between five times of the first and four... (answered by stanbon)

The second of two numbers is three times the first. The difference between five times the (answered by mananth)

The sum of two numbers is 20. The difference between three times the first number and... (answered by josgarithmetic,ankor@dixie-net.com,stanbon)

I am thinking of two numbers. The sum of the first and twice the second is 34. The... (answered by advanced_Learner)

Two numbers have sum of 32. If the second is five less than four times the first, what... (answered by ankor@dixie-net.com)

Two numbers have a sum of twenty. If the second is five less than four times the first,... (answered by mathmartian)

the sum of two numbers is 59. the difference between 2 times the first number and 6 times (answered by jorel1380)

the sum of two numbers is 45. 4 times the first number is 9 less than 5 times the second. (answered by algebrahouse.com)