SOLUTION: John is 12 years older than Susan. The sum of their age is 42. How old is each?

Question 827513: John is 12 years older than Susan. The sum of their age is 42. How old is each?
Answer by TimothyLamb(4379) (Show Source): You can put this solution on YOUR website!
---
x = john
y = susan
---
x = y + 12
x + y = 42
---
put the system of linear equations into standard form:
---
x - y = 12
x + y = 42
---
copy and paste the above linear system in standard form into this matrix-method solver:
https://sooeet.com/math/system-of-linear-equations-solver.php
---
solution:
x = john = 27
y = susan = 15
---
system matrix
1 -1
1 1
---
inverse of system matrix
0.5 0.5
-0.5 0.5
---
determinant of system matrix = 2
---
Solve and graph linear equations:
https://sooeet.com/math/linear-equation-solver.php
---
Solve quadratic equations, quadratic formula:
https://sooeet.com/math/quadratic-formula-solver.php
---
Solve systems of linear equations up to 6-equations 6-variables:
https://sooeet.com/math/system-of-linear-equations-solver.php
RELATED QUESTIONS
Mary is twice as old as Susan and three years older than John. The sum of their ages is... (answered by drk)

john is 10 years older than susan. five years ago, the sum of their ages was 34. how old... (answered by josgarithmetic)

[Demola is 2 years older than john, peter is half of demola's age, the sum of their ages... (answered by TimothyLamb,MathTherapy)

John is two years older than James, and Matt is half John's age, the sum of their age is... (answered by Edwin McCravy)

Mary is 24 years older than her son John. The sum of their ages is 40. How old is John? (answered by rfer,Alan3354)

John is 2 years older than bill . If the sum of their ages is 36 , how old is john... (answered by ikleyn)

John is 5 years older than Yaw,if the sum of their ages is 19.How old is John (answered by Shin123,ikleyn)

Ann is 5 years older than her sister Susan. The sum of their ages is 27. How old is each... (answered by ewatrrr)

Ben is 12 years older than Sally. The sum of their age is 50. How old is Ben... (answered by Alan3354)