Ask Singapore Homework?

Upload a photo of a Singapore homework and someone will email you the solution for free.



Question

secondary 3 | A Maths
5 Answers Below

Anyone can contribute an answer, even non-tutors.

Answer This Question
Tarah toh
Tarah Toh

secondary 3 chevron_right A Maths chevron_right Singapore

Help pleaseeeee

Date Posted: 3 months ago
Views: 29
Eric Nicholas K
Eric Nicholas K
3 months ago
Hi Tarah! I will do up the answers at 1 am if no one has already solved them by then.
snell
Snell
3 months ago
(a)(i)
log₅(x²-5x+20) = 1/log₂5 + 1/log₇5
=> log₅(x²-5x+20) = log2/log5 + log7/log5

=> log₅(x²-5x+20) = log₅2 + log₅7

=> log₅(x²-5x+20) = log₅14

=> x²-5x+20 = 14

=> x²-5x+6 = 0

=> (x-2)(x-3) = 0

=> x = 2 or 3



(a)(ii)
lg y² = (lg y)²
=> 2lg y = (lg y)²
=> (lg y)² - 2lg y = 0
=> lg y(lg y-2) = 0
=> lg y = 0 or lg y - 2 = 0
=> y = 1 or lg y = 2
=> y = 1 or y = 100


(b)
8e⁴ˣ - 15e²ˣ - 2 = 0
=> 8(e²ˣ)² - 15e²ˣ - 2 = 0
=> (8e²ˣ + 1)(e²ˣ - 2) = 0
=> e²ˣ = -1/8 (n.a.) or e²ˣ = 2
=> e²ˣ = 2
=> 2x = ln 2
=> x = (ln 2)/2 = 0.347


...

See 5 Answers

done {{ upvoteCount }} Upvotes
clear {{ downvoteCount * -1 }} Downvotes
Eric Nicholas K
Eric Nicholas K's answer
3837 answers (Tutor Details)
1st
Hi Tarah! Here are my workings for these questions. Let me know if you need more explanation on these.
Tarah toh
Tarah Toh
3 months ago
Clear steps
Eric Nicholas K
Eric Nicholas K
3 months ago
Ok, will write them up later or tmr when I am free
done {{ upvoteCount }} Upvotes
clear {{ downvoteCount * -1 }} Downvotes
Eric Nicholas K
Eric Nicholas K's answer
3837 answers (Tutor Details)
Before I proceed, here are certain laws of logarithms which you will need to know.
done {{ upvoteCount }} Upvotes
clear {{ downvoteCount * -1 }} Downvotes
Eric Nicholas K
Eric Nicholas K's answer
3837 answers (Tutor Details)
Here are my insights into how to solve Q1 a(i). In red are my explanations; in blue are the workings to include when you write up your answers.
done {{ upvoteCount }} Upvotes
clear {{ downvoteCount * -1 }} Downvotes
Eric Nicholas K
Eric Nicholas K's answer
3837 answers (Tutor Details)
Hi Tarah! Here are my explanations for Q1 a(ii).
done {{ upvoteCount }} Upvotes
clear {{ downvoteCount * -1 }} Downvotes
Eric Nicholas K
Eric Nicholas K's answer
3837 answers (Tutor Details)
And finally, this is for Q1 b.

I hope my explanations and workings help! Let me know if you still need more explanation for my workings and I will explain them again!