21 less than a is 11.... how would this be put in a algebraic equation?

Question

i'm stuck on this problem and don't know how to do it i've never done a problem like this so please help 

Answer 1

These types of problems are awkward mainly because they come from a math book. When you are reading a problem and see the words "is" or "has" you can translate that to '='.

With phrases like "5 more than x" or "5 greater than x" you can translate that to be 5+x which is the same as x+5.

With the phrase like "5 less than x" we have to be careful because 5-x is not the same as x-5.  But you probably will naturally set this problem up correctly if we put it into a real life context: You have 5 less candies than your friend, who has 8. How many do you have?  You probably automatically know that you have 3 because you did 8-5.

So for your problem do the same thing.

"21 less than a"  translates to  ' a-21 '  "is 11"  translates to ' =11 '

 

Thus altogether you get the math problem:  a-21=11  and then you can solve this.

  

Answer 2

EQUATION:   a - 21 = 11 

 

Note: left side says 21 less than a (because you start with a and subtract 21)