2(a+7)-7=9

Question

Trying to help out son

Answer 1

a = 1

 

When doing any math problems, one must follow the law of operations: P.E.M.D.A.S.

 

P = Parentheses

E = Exponents

M = Multiplication

D = Division

A= Addition

S = Subtraction

 

 

So..

 

2(a+7) - 7 = 9 

(2 x a) + (2 x 7) - 7 = 9

   2a    +    14    -  7 = 9

   2a    +          7      = 9

                     -7         -7   (Subtract 7 from both sides of the equation to isolate the variable (a))

_____________________

          2a               =  2

         /2                    /2  (Divide by 2 to isolate the variable, a)

 _____________________

            a              = 1

 

 

Answer 2

 

Hey Corine -- you may like vocalizing "double the 'a' and the '7' ... remove a '7' to get 9"

"spelling it out"  a+a + 7+7 -7 =9 ... a+a +7 =9 ... 7 needs 2 ones to reach 9 => each "a" is 1

Answer 3

The objective is to isolate the variable. first distribute the 2 to the terms in the parentheses.

 

2(a+7)-7=9   

2a+14-7=9

 

Combine like terms on left side of equation.

 

2a+7=9

 

Use the inverse operation of subtraction to isolate term with variable to one side alone.

 

2a+7-7=9-7

2a=2

 

Divide both sides by 2 

 

a=1