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a(a² - 4) - a[a + a(a - 2)] cant get answer right -.-?
a(a² - 4) - a[a + a(a - 2)]
3 Answers
- Anonymous5 years ago
Update: a(a² - 4) - a[a + a(a - 2)]
to expand the expression, simply distribute and combine like terms...
a³ - 4a - a[a + a² - 2a] = a³ - 4a - a(a² - a) = a³ - 4a - a³ + a² = a² - 4a
Using a "little" care never hurts !!
- 5 years ago
expand out all brackets first
a^3 -4a - a(a+a^2 -2a) dont for get that this final bracket is being multiplied by -a
a^3 - 4a - a^2 - a^3 + 2a^2 a^3's cancel out and other simplifications
a^2 - 4a ta-dah a quadratic
to find roots (usually what question is asking for) assume that it equals 0
a^2 -4a = 0
a^2 = 4a
a = 4
- spot aLv 75 years ago
a(a² - 4) - a[a + a(a - 2)]
= a^3 - 4a - a[a + a^2 - 2a]
= a^3 - 4a -a^2 + a^3 -2a^2
= 2a^3 - 3a^2 - 4a
