Question 213997
The sum of two numbers is 84. The first is 9 more than 4 times the second. Find the first number.


Step 1.  Let x be the second number.  Let 9+4x is be first number.


Step 2.  x+9+4x=84  The sum of two numbers is 84.


Step 3.  Simplify:  5x+9=84.


Step 4.  Subtract 9 to both sides of equation:  5x+9-9=84-9=75


Step 5.  Simplify and divide by 5:  5x=75 or x=15.  Then 9+4x=9+4(15)=69


Step 6.  The first number is 69.


I hope the above steps were helpful. 


For free Step-By-Step Videos on Introduction to Algebra, please visit http://www.FreedomUniversity.TV/courses/IntroAlgebra or for Trigonometry visit http://www.FreedomUniversity.TV/courses/Trigonometry.


And good luck in your studies!


Respectfully,
Dr J