Eric Nicholas K's answer to Kathy's Secondary 4 A Maths Singapore question.
done
{{ upvoteCount }} Upvotes
clear
{{ downvoteCount * -1 }} Downvotes
The relevant steps to solve cubic equations are as follows.
1. Guess a number which fits the equation. Typically whole numbers for your syllabus. Note that if the equation is not cubic, but say power 4, we need to guess two numbers. If power 5, three numbers. And so on.
2. Transform the guessed number into a factor. For example, if x = 1 is a solution, then (x - 1) is a factor.
3. Perform long division of the cubic expression with the factor to obtain a quotient in the form Ax2 + Bx + C and then factorise the expression. Alternatively, you can do comparing coefficients method. Since you have factored out a linear expression from a cubic equation, you will obtain a quadratic term (as per what I wrote).
4. We proceed to solve the equation in the factorised form.
1. Guess a number which fits the equation. Typically whole numbers for your syllabus. Note that if the equation is not cubic, but say power 4, we need to guess two numbers. If power 5, three numbers. And so on.
2. Transform the guessed number into a factor. For example, if x = 1 is a solution, then (x - 1) is a factor.
3. Perform long division of the cubic expression with the factor to obtain a quotient in the form Ax2 + Bx + C and then factorise the expression. Alternatively, you can do comparing coefficients method. Since you have factored out a linear expression from a cubic equation, you will obtain a quadratic term (as per what I wrote).
4. We proceed to solve the equation in the factorised form.
Date Posted:
5 years ago
Can help me out the rest?
Ok, one at a time, but not all today
360 Tutoring Program