Login | Register
Enrol now for our new online tutoring program. Learn from the best tutors. Get amazing results. Learn more.

Welcome, Guest. Please login or register.

June 26, 2022, 11:39:57 am

Author Topic: algebra help  (Read 1283 times)  Share 

0 Members and 1 Guest are viewing this topic.

annaoh_2003

  • Trailblazer
  • *
  • Posts: 31
  • Respect: 0
algebra help
« on: January 16, 2022, 10:06:09 pm »
0
Hi, im wondering if someone can explain to me how to solve this equation??
« Last Edit: January 16, 2022, 10:08:32 pm by annaoh_2003 »

mabajas76

  • Forum Obsessive
  • ***
  • Posts: 201
  • Respect: +13
Re: algebra help
« Reply #1 on: January 16, 2022, 10:30:36 pm »
+2
So here is the trick, you can assign 2^x a value, lets say t. So 2^2x=t^2, -15x2^x=-15t etc
So you get t^2-15t-16=0, the soloutions for this are t= 16 or -1, using t=16 you get 16=2^x, then 16=2^4 and so x=4.
"Don't give up, and don't put too much effort into things that don't matter"-Albert Einstein, probably.

Pariz

  • Fresh Poster
  • *
  • Posts: 2
  • Respect: 0
Re: algebra help
« Reply #2 on: February 19, 2022, 10:35:34 am »
0
Hey - for these types of questions you pretty much wanna reduce it to a simpler quadratic equation.
 
you would let a = 2^x, then substitute into given equation.

so you get

a^2-15a-16=0
(a-16)(a+1)=0
a=16 or a=-1
You ALWAYS reject negatives. resub back to solve for x

2^x=16=2^4
and so x=4

(Mod edit) -redacted link- sharing of external groups isn't allowed on the forum. Please consult forum rules :)

hope it helped
« Last Edit: February 19, 2022, 06:21:01 pm by insanipi »