Loading [MathJax]/jax/output/SVG/jax.js
 
  Questions   
Sort: 
 #2
avatar+33657 
+2
Nov 4, 2020
 #1
avatar+118704 
+2

Hi May,

It is nice to meet you.

What you have done is completely correct.

You should state right from the beginning that      

2x<6

 

so you have 

2x(x6)(2x15)=162

From the way the question is worded, it seems likely that the answer will be an integer

so

You could just plug in x=2,3,4 5  and see if one of them works frown

 

-----------------------

 

However, if none of those work, or if you want to do it in a more complicated way then here is an alternative.

 

Expand it and take it all to the same side. (start by dividing both sides by 2)

You will get

 

2x327x2+90x81=0

You need to look for factors and the way the question is worded it seems that there will most likely be an integer value of x

If there is an integer one to find it will be a factor of 81.

choices   

±1,±3,±81

[edit: I forgot  +/-9]

 

I usually look at the plus and minus at the same time as it saved time, but I am hoping for a pos one so not this time

 

Normally Id start with  +/-1 but we are looking for one between 2 and 6   so I will try 3

If x=3 then

LHS=2*27-27*9+90*3-81 = 0 = RHS

So x=3 will make this work.

 

You can continue on to look for other possibilities if you want but you already have your answer.

--------------------

 

If you were going to continue then you would  use algebraic division for this.

(2x327x2+90x81)÷(x3)   

The you would use the quadratic formula to find the other 2 solutions.

 

.
Nov 4, 2020

0 Online Users