## Ask Singapore Homework?

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

## Question

secondary 3 | A Maths

Anyone can contribute an answer, even non-tutors.

##### Tarah Toh

chevron_right chevron_right

Date Posted: 1 week ago
Views: 14
Eric Nicholas K
1 week ago
Hi Tarah! I will do up the answers at 1 am if no one has already solved them by then.
Snell
1 week 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's answer
2984 answers (Tutor Details)
1st
Hi Tarah! Here are my workings for these questions. Let me know if you need more explanation on these.
Date Posted: 1 week ago
Tarah Toh
1 week ago
Clear steps
Eric Nicholas K
1 week ago
Ok, will write them up later or tmr when I am free
done {{ upvoteCount }} Upvotes
clear {{ downvoteCount * -1 }} Downvotes
##### Eric Nicholas K's answer
2984 answers (Tutor Details)
Before I proceed, here are certain laws of logarithms which you will need to know.
Date Posted: 1 week ago
done {{ upvoteCount }} Upvotes
clear {{ downvoteCount * -1 }} Downvotes
##### Eric Nicholas K's answer
2984 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.
Date Posted: 1 week ago
done {{ upvoteCount }} Upvotes
clear {{ downvoteCount * -1 }} Downvotes
##### Eric Nicholas K's answer
2984 answers (Tutor Details)
Hi Tarah! Here are my explanations for Q1 a(ii).
Date Posted: 1 week ago
done {{ upvoteCount }} Upvotes
clear {{ downvoteCount * -1 }} Downvotes
##### Eric Nicholas K's answer
2984 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!
Date Posted: 1 week ago