Question 1173361
  <pre><font face = "Tohoma" size = 3 color = "indigo"><b> 
Hi, 
Four times a number minus 5 times another number is equal to 21.
Inserting x and y in the sentence
Four times a number {{{highlight_green(x)}}} minus 5 times another number {{{highlight_green(y)}}} is equal to 21
Gives us:  4x - 5y = 21
Three times the sum of the two numbers is 36
Gives us:  3(x+y) = 36   0r  x + y = 12
Two Equations, Two Unknowns
 4x - 5y = 21
  x +  y = 12  
Multiplying 2nd Equation by 5 to eliminate y
 4x - 5y = 21
<u>5x + 5y = 60</u>
 9x = 81
   x = 9   and y = 3   {{{ x +  y = 12 }}}
Two Numbers are 9  an 3
checking our Answer
 4x - 5y = 21
 36 - 15 = 21  checks.
Wish You the Best in your Studies.