Leaving cert higher level maths

seller285

Wondering if anyone could help me with this question that's been wrecking my head. I've posted it onto a maths teacher forum before but they've only "pointed me in the right direction" with it and wasn't much help at all.
It's an algebra expression from text + tests 6:

((a+b)/(a-b)-(a-b)/(a+b))/1+((a-b)/(a+b))

lollipop95mal

Anybody have the solutions to this sum:

2x-3+4x (the x-3 is suppossed to be above the 2 in smaller writing)

16
---- = 2x+y (x+y is also in smaller writing)
2x

Answers must be -3 and 10

pinkbear

Seller285: I think this is what you are looking for.....
(Note: "Top" refers to everything above the solid line, "Bottom" to everything beneath)

(a+b) - (a-b)

---

---

(a-b) (a+b)
____________
1 + (a-b)

---

(a+b)


(a+b)(a+b) - (a-b)(a-b)

---

(a-b)(a+b)
______________________ Taking common denominator (a-b)(a+b) on top and (a+b) on bottom
(a+b) + (a-b)

---

(a+b)


(a+b)(a+b) - (a-b)(a-b)

---

(a-b)
_____________________ Multiplying top and bottom by (a+b)
(a + b) + (a - b)


a^2 + 2ab + b^2 - (a^2 - 2ab + b^2)

---

(a-b)
___________________________ Multiplying out the top and the bottom a bit
2a


a^2 + 2ab + b^2 - a^2 +2ab - b^2)

---

(a-b)
___________________________ Removing brackets on top
2a

4ab

---

(a-b)
__________ Adding / subtracting top
2a


4ab 1

---

x --- Turn bottom upsidedown and multiply
(a-b) 2a


2b

---

Cancelling down
a-b

pinkbear

Hi Lollipop.... Need a bit more information.
Is there supposed to be "=" somewhere in the first equation??
When you say "above the 2 in smaller writing" do you mean it's 2^(x-3), i.e. 2 to the power of (x-3)
Are we looking for the values of x and y?

lollipop95mal wrote: »

Anybody have the solutions to this sum:

2x-3+4x (the x-3 is suppossed to be above the 2 in smaller writing)

16
---- = 2x+y (x+y is also in smaller writing)
2x

Answers must be -3 and 10