GainzGucci
Badges: 0
Rep:
?
#1
Report Thread starter 5 years ago
#1
Can someone show some step by step solutions to these two questions

Thank You in advance.
Attached files
0
reply
WhiteGroupMaths
Badges: 9
Rep:
?
#2
Report 5 years ago
#2
Full solutions are not to be shared on this forum.

I will get you started on Q7.

3^(2x+1) * 9^x = 27

3^(2x+1) * (3^2)^x = 27

3^(2x+1) * (3^2x)= 27

Can you use the law a^b * a^c = a^ (b+c) now?

Can you therefore solve for x subsequently using simple logarithms?

Peace.
1
reply
bobjon22444
Badges: 2
Rep:
?
#3
Report 5 years ago
#3
You cant use logs its C1
0
reply
bobjon22444
Badges: 2
Rep:
?
#4
Report 5 years ago
#4
(Original post by WhiteGroupMaths)
Full solutions are not to be shared on this forum.

I will get you started on Q7.

3^(2x+1) * 9^x = 27

3^(2x+1) * (3^2)^x = 27

3^(2x+1) * (3^2x)= 27

Can you use the law a^b * a^c = a^ (b+c) now?

Can you therefore solve for x subsequently using simple logarithms?

Peace.
You cant use logs its C1
0
reply
Andy98
  • Study Helper
Badges: 20
Rep:
?
#5
Report 5 years ago
#5
(Original post by bobjon22444)
You cant use logs its C1
Yes you can.

Posted from TSR Mobile
0
reply
Kholmes1
Badges: 18
Rep:
?
#6
Report 5 years ago
#6
(Original post by Andy98)
Yes you can.

Posted from TSR Mobile
Maybe it depends on the exam board. But you don't learn logs until c2.
0
reply
bobjon22444
Badges: 2
Rep:
?
#7
Report 5 years ago
#7
(Original post by Kholmes1)
Maybe it depends on the exam board. But you don't learn logs until c2.
The question is from an edexcel paper. So indices laws should be used not logs. Because for logs a calculator is required
0
reply
bobjon22444
Badges: 2
Rep:
?
#8
Report 5 years ago
#8
Lol I just want to solutions. The answer to both is x=1/2 but I want to know how it got there, stupid books dont give solutions.
0
reply
Kholmes1
Badges: 18
Rep:
?
#9
Report 5 years ago
#9
(Original post by bobjon22444)
The question is from an edexcel paper. So indices laws should be used not logs. Because for logs a calculator is required
Yeah thats what I thought as well. You can't use it in c1. Do you know what paper it is? Exam Solutions is good.
0
reply
Andy98
  • Study Helper
Badges: 20
Rep:
?
#10
Report 5 years ago
#10
(Original post by Kholmes1)
Maybe it depends on the exam board. But you don't learn logs until c2.
(Original post by bobjon22444)
The question is from an edexcel paper. So indices laws should be used not logs. Because for logs a calculator is required
Oh yeah. I forgot they called them indices laws in C1 but it is the same principle

Posted from TSR Mobile
0
reply
zigocarn
Badges: 8
Rep:
?
#11
Report 5 years ago
#11
(Original post by WhiteGroupMaths)
Full solutions are not to be shared on this forum.

I will get you started on Q7.

3^(2x+1) * 9^x = 27

3^(2x+1) * (3^2)^x = 27

3^(2x+1) * (3^2x)= 27

Can you use the law a^b * a^c = a^ (b+c) now?

Can you therefore solve for x subsequently using simple logarithms?

Peace.
Is the answer for part a, x= 1/2?
0
reply
bobjon22444
Badges: 2
Rep:
?
#12
Report 5 years ago
#12
Its from a pearson book called revisons work book. I cant seem to find the solutions either.
0
reply
troubadour.
Badges: 19
#13
Report 5 years ago
#13
These aren't surds...
0
reply
bobjon22444
Badges: 2
Rep:
?
#14
Report 5 years ago
#14
(Original post by zigocarn)
Is the answer for part a, x= 1/2?
Yes but how did you get it. It must be without logs.
0
reply
bobjon22444
Badges: 2
Rep:
?
#15
Report 5 years ago
#15
(Original post by Hydeman)
These aren't surds...
LOL no its index laws.
0
reply
troubadour.
Badges: 19
#16
Report 5 years ago
#16
(Original post by bobjon22444)
LOL no its index laws.
Yes, which is why I'm wondering why the thread advertises it as a surd problem...
1
reply
zigocarn
Badges: 8
Rep:
?
#17
Report 5 years ago
#17
(Original post by bobjon22444)
Yes but how did you get it. It must be without logs.
It's simple.
What you want to do first is make the bases the same for all three values.
Once the bases are the same, you are able to add the powers.
Remember that the power for both sides are equal to each other and this is why you can solve for x.
0
reply
Andy98
  • Study Helper
Badges: 20
Rep:
?
#18
Report 5 years ago
#18
(Original post by bobjon22444)
Yes but how did you get it. It must be without logs.
Make everything be in the form of 3 to the power something. For example 27 would be 3^3.

Then use the rule a^z*a^y=a^{z+y} to solve for x

Posted from TSR Mobile
1
reply
bobjon22444
Badges: 2
Rep:
?
#19
Report 5 years ago
#19
(Original post by Andy98)
Make everything be in the form of 3 to the power something. For example 27 would be 3^3.

Then use the rule a^z*a^y=a^{z+y} to solve for x

Posted from TSR Mobile
so 3^2x+1*3^2=3^3 then add powers ?
0
reply
Andy98
  • Study Helper
Badges: 20
Rep:
?
#20
Report 5 years ago
#20
(Original post by bobjon22444)
so 3^2x+1*3^2=3^3 then add powers ?
:yep:

Posted from TSR Mobile
0
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts
Back
to top
Latest
My Feed

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise

Poll: What factors affect your mental health most right now? Post-lockdown edition

Anxiousness about restrictions easing (27)
5.73%
Uncertainty around my education (53)
11.25%
Uncertainty around my future career prospects (56)
11.89%
Lack of purpose or motivation (62)
13.16%
Lack of support system (eg. teachers, counsellors, delays in care) (26)
5.52%
Impact lockdown had on physical health (21)
4.46%
Social worries (incl. loneliness/making friends) (49)
10.4%
Financial worries (29)
6.16%
Concern about myself or my loves ones getting/having been ill (19)
4.03%
Exposure to negative news/social media (31)
6.58%
Difficulty accessing real life entertainment (14)
2.97%
Lack of confidence in making big life decisions (46)
9.77%
Worry about missed opportunities during the pandemic (38)
8.07%

Watched Threads

View All