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secondary 3 | A Maths
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Piano guy potato
Piano Guy Potato

secondary 3 chevron_right A Maths chevron_right Singapore

Please help with the circled parts

Date Posted: 4 years ago
Views: 172
J
J
4 years ago
f(x) = ax + b

For the inverse,

x = af-¹(x) + b

For f-¹(7) = -1,


7 = a(-1) + b

7 = -a + b

b = 7 + a

Since 3a - b = 3 from i),

3a - (7 + a) = 3

2a - 7 = 3

2a = 10

a = 5

So b = 7 + 5 = 12
J
J
4 years ago
h(x) = (4x + 5)/(x - 1)

For the inverse,

x = (4h-¹(x) + 5)/(h-¹(x) - 1)

xh-¹(x) - x = 4h-¹(x) + 5

(x - 4) h-¹(x) = x + 5

h-¹(x) = (x + 5)/(x - 4)


When 2h-¹(2x) = x,

2(2x + 5)/(2x - 4) = x

2(2x + 5) = x(2x - 4)

4x + 10 = 2x² - 4x

2x² - 8x - 10 = 0

x² - 4x - 5 = 0

(x - 5)(x + 1) = 0

x = 5 or x = -1
Piano guy potato
Piano Guy Potato
4 years ago
Thanks

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Piano guy potato
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Thanks J!