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### History and Feedback

#### Checkpoint description

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Published this.

#### Christian Lawson-Perfect2 years, 4 months ago

Gave some feedback: Ready to use

#### Christian Lawson-Perfect2 years, 4 months ago

Saved a checkpoint:

I'm not sure why part b had two equations in it. I've split it into two parts.

A couple of uses of "question" instead of "equation" in the advice.

The quadratic formula was missing $x=$ a few times in the advice!

Otherwise, this is good.

#### Hannah Aldous2 years, 4 months ago

Gave some feedback: Needs to be tested

#### Chris Graham2 years, 4 months ago

Nearly there!

In the steps you'll need to give the form of the quadratic equation associated with the solution, to assist the student in identifying $a$, $b$ and $c$.

#### Chris Graham2 years, 4 months ago

Gave some feedback: Has some problems

#### Hannah Aldous2 years, 4 months ago

Gave some feedback: Needs to be tested

#### Chris Graham2 years, 4 months ago

I have changed the wording of the statement slightly and also removed "require trailing zeros" in part (a), which was too harsh.

I've removed (i) from part (a) as there is only one sub-part.

Otherwise looks good. However, if this is the first time we meet the quadratic formula (I'm guessing from the way the statement is worded) then I would like to have it available to the student, perhaps as a step to part (a)?

#### Chris Graham2 years, 4 months ago

Gave some feedback: Has some problems

#### Hannah Aldous2 years, 4 months ago

Gave some feedback: Needs to be tested

#### Vicky Hall2 years, 4 months ago

Gave some feedback: Has some problems

#### Vicky Hall2 years, 4 months ago

I would give the quadractic formula in the statement and have $x=$ in front of it. I would amend the statement so that it says it can also be useful to use the formula if equations are difficult to factorise (perhaps if coefficients are large), as the equations in part a) and part b)i) could both be solved by factorising instead but using the formula is (probably) quicker.

The expected answers in part a) are the numbers that would appear in the factorised equation and not the roots so you need to negate the answers and then swap their gaps around.

#### Hannah Aldous2 years, 4 months ago

Gave some feedback: Needs to be tested

#### Christian Lawson-Perfect2 years, 4 months ago

Gave some feedback: Has some problems

#### Christian Lawson-Perfect2 years, 4 months ago

The non-zero right-hand sides in part a are gotchas: I'd like to have a nice part first, where the right-hand side is zero.

Could you make the coefficients in part b work so that you get integers out? You want to see if the student can work out how to deal with getting an algebraic answer, and rounding errors would be a distraction.

In part b it looks like the roots are the wrong way round - the lowest root is second.

You could split this into two questions: "use the quadratic formula to solve an equation with non-zero RHS", and "use the quadratic formula to solve an equation in terms of another variable".

#### Hannah Aldous2 years, 4 months ago

Gave some feedback: Needs to be tested

#### Lauren Richards2 years, 4 months ago

• Your i) and ii) need to be not bold and in italics in the parts.
• The quadratic formula equation in the start of the advice is slightly incorrect - it should be 2a on the denominator, not 2.
• Something is not quite right for a)ii) in the advice as it is written as it would be when writing it and also midway through the advice for part b).

#### Lauren Richards2 years, 4 months ago

Gave some feedback: Has some problems

#### Hannah Aldous2 years, 4 months ago

Gave some feedback: Needs to be tested

#### Hannah Aldous2 years, 5 months ago

Created this.
Using the Quadratic Formula to Solve Equations of the Form $ax^2 +bx+c=0$ Ready to use Hannah Aldous 01/08/2017 14:06
Use the quadratic formula to solve an equation in terms of an unknown variable Ready to use Hannah Aldous 01/08/2017 13:56
Katherine's copy of Using the Quadratic Formula to Solve Equations of the Form $ax^2 +bx+c=0$ draft Katherine Tomlinson 02/08/2017 12:45
Emma's copy of Using the Quadratic Formula to Solve Equations of the Form $ax^2 +bx+c=0$ draft Emma Cliffe 31/08/2017 12:59
Peter's copy of Using the Quadratic Formula to Solve Equations of the Form $ax^2 +bx+c=0$ draft Peter Knowles 12/09/2017 12:39
Using the Quadratic Formula to Solve Equations of the Form $ax^2 +bx+c=0$ [L4 Randomised] Needs to be tested Matthew James Sykes 25/07/2018 11:06
Simon's copy of Using the Quadratic Formula to Solve Equations of the Form $ax^2 +bx+c=0$ draft Simon Thomas 07/03/2019 09:55
Simon's copy of Use the quadratic formula to solve an equation in terms of an unknown variable draft Simon Thomas 07/03/2019 10:00
Use the quadratic formula to solve an equation in terms of an unknown variable draft Xiaodan Leng 11/07/2019 01:50
Solve Equations of the Form $ax^2 +bx+c=0$ draft Thomas Waters 11/09/2019 22:18
Michael's copy of Solve Equations of the Form $ax^2 +bx+c=0$ draft Michael Proudman 09/10/2019 08:25
Blathnaid's copy of Use the quadratic formula to solve an equation in terms of an unknown variable draft Blathnaid Sheridan 21/10/2019 12:19
Blathnaid's copy of Use the quadratic formula to solve an equation in terms of an unknown variable draft Blathnaid Sheridan 21/10/2019 12:33

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