Math Is Fun Forum

sologuitar

Member

Registered: 2022-09-19

Posts: 467

Factoring Equations With Decimals

Factor 2.3x^2 + 1.4x - 4.5 = 0 without a calculator.

What is the best method to use for factoring equations with decimals without a calculator?

You say?

Bob

Administrator

Registered: 2010-06-20

Posts: 10,640

Re: Factoring Equations With Decimals

2.3x^2 + 1.4x - 4.5 = 0

Wolfram Alpha doesn't get an easy factorisation here. Are you sure that's copied correctly.  But WA does do what I'd do anyway which is to remove the 2.3 as a 'common' factor:

You can then complete the square as shown elsewhere, but you don't get rational coefficients so use of a calculator is essential hence why I question the posted quadratic.

Bob

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Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei
Sometimes I deliberately make mistakes, just to test you!  …………….Bob

sologuitar

Member

Registered: 2022-09-19

Posts: 467

Re: Factoring Equations With Decimals

2.3x^2 + 1.4x - 4.5 = 0

Wolfram Alpha doesn't get an easy factorisation here. Are you sure that's copied correctly.  But WA does do what I'd do anyway which is to remove the 2.3 as a 'common' factor:

You can then complete the square as shown elsewhere, but you don't get rational coefficients so use of a calculator is essential hence why I question the posted quadratic.

Bob

Maybe it is a typo at my end. What about if I clear the decimal numbers multiplying by a whole number(s) that would allow me to do so?

Example:

Say the coefficient of the x^2 term is 0.10.
I can multiply 0.10 by 100 to get 10. Can this be done to the decimal
numbers given in this question (considering it is not a typo)?

amnkb

Member

Registered: 2023-09-19

Posts: 253

Re: Factoring Equations With Decimals

Factor 2.3x^2 + 1.4x - 4.5 = 0 without a calculator.

What is the best method to use for factoring equations with decimals without a calculator?

i'd multiply thru by 10 to get rid of the decimal pts

then do the Quadratic Formula
answer is messy

sologuitar

Member

Registered: 2022-09-19

Posts: 467

Re: Factoring Equations With Decimals

Factor 2.3x^2 + 1.4x - 4.5 = 0 without a calculator.

What is the best method to use for factoring equations with decimals without a calculator?

i'd multiply thru by 10 to get rid of the decimal pts

then do the Quadratic Formula
answer is messy

This is exactly what I thought about doing at first. I don't mind messy answers as long as it is right.