# Isosceles Simultaneous Equations

I'm self studying for a Maths AS-Level...

I've got a tricky question that I'm struggling with, if someone could point me in the right direction it would be appreciated

Neither attempt matches the book answer
(edited 1 year ago)

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Original post by Ellie Lemaine
I'm self studying for a Maths AS-Level...

I've got a tricky question that I'm struggling with, if someone could point me in the right direction it would be appreciated

Neither attempt matches the book answer

Not fully following your attempt, but you seem to/should have
side1 = side2
side1 + side2 + side3 = 150
As both of those are linear in p and q, it should just be a couple of linear simultaneous equations in the two variables, so either elimination or substitution should work.
Original post by Ellie Lemaine
I'm self studying for a Maths AS-Level...

I've got a tricky question that I'm struggling with, if someone could point me in the right direction it would be appreciated

Neither attempt matches the book answer

Can you write down what you did to get the perimeter? I can't see an equation that matches mine.
you can set up two equations, one for the perimeter and one that leverages the fact isosceles have two sides that are equal.
Then solve them.
Original post by shrimpbody
...

(edited 1 year ago)
will do
Original post by mqb2766
Original post by shrimpbody
will do

Best to delete the attempt and let the OP do as much work as possible.
Original post by Muttley79
Can you write down what you did to get the perimeter? I can't see an equation that matches mine.

It was given as part of question 5
Perimeter is the total length of all sides of a shape
Original post by Ellie Lemaine
It was given as part of question 5
Original post by Ellie Lemaine
It was given as part of question 5

Yes I know but where have you written that information as an equation?
she has but added 150 to the side equation
Original post by Muttley79
Yes I know but where have you written that information as an equation?
line three of her workings top right
Original post by shrimpbody
she has but added 150 to the side equation

I've written one as p-2q=-10 and the other as 3p-q=145
Original post by shrimpbody
she has but added 150 to the side equation

It's not correct though - al three sides need to be added to get a perimeter and I can't see that anywhere
Original post by Ellie Lemaine
I've written one as p-2q=-10 and the other as 3p-q=145

Try the second one again - write out the three sides as a sum = 150
double check that second equation, don't think its right
Original post by Ellie Lemaine
I've written one as p-2q=-10 and the other as 3p-q=145
I agree but seems op tried to do something with perimeter and got confused
Original post by Muttley79
It's not correct though - al three sides need to be added to get a perimeter and I can't see that anywhere
Original post by shrimpbody
double check that second equation, don't think its right

It's finally given me the right solution for q... the answer says q = 25
what did you get for p
Original post by Ellie Lemaine
It's finally given me the right solution for q... the answer says q = 25
Original post by shrimpbody
what did you get for p

40 which corresponds from the book