Ask Singapore Homework?
Upload a photo of a Singapore homework and someone will email you the solution for free.
Question
secondary 3 | A Maths
No Answers Yet
Anyone can contribute an answer, even non-tutors.
help rn pls
Date Posted: 4 years ago
Views: 264
f(x) = 2x³ + ax² - 7a²x - 6a³
(i)
f(-a) = -2a³ + a³ + 7a³ - 6a³ = 0
(x+a) is a factor of f(x)
(ii)
f(x) = 0
2x³ + ax² - 7a²x - 6a³ = 0
*do long division
. . . . . . . 2x² - ax - 6a²
(x+a) √2x³ + ax² - 7a²x - 6a³
. . . . . - ) 2x³ + 2ax²
. . . . . . . . . . . . - ax² - 7a²x
. . . . . . . . . . - ) - ax² - a²x
. . . . . . . . . . . . . . . . . . . - 6a²x - 6a³
. . . . . . . . . . . . . . . . . . . - 6a²x - 6a³
=> 2x³ + ax² - 7a²x - 6a³ = 0
=> (x+a)(2x² - ax - 6a²) = 0
=> (x+a)(2x + 3a)(x - 2a) = 0
=> (x = -a or -3a/2 or 2a
.
.
.
(i)
f(-a) = -2a³ + a³ + 7a³ - 6a³ = 0
(x+a) is a factor of f(x)
(ii)
f(x) = 0
2x³ + ax² - 7a²x - 6a³ = 0
*do long division
. . . . . . . 2x² - ax - 6a²
(x+a) √2x³ + ax² - 7a²x - 6a³
. . . . . - ) 2x³ + 2ax²
. . . . . . . . . . . . - ax² - 7a²x
. . . . . . . . . . - ) - ax² - a²x
. . . . . . . . . . . . . . . . . . . - 6a²x - 6a³
. . . . . . . . . . . . . . . . . . . - 6a²x - 6a³
=> 2x³ + ax² - 7a²x - 6a³ = 0
=> (x+a)(2x² - ax - 6a²) = 0
=> (x+a)(2x + 3a)(x - 2a) = 0
=> (x = -a or -3a/2 or 2a
.
.
.
ok ty
360 Tutoring Program