Basically, i don't understand how numbers, when on the outside of the first bracket, effect the equation when its brackets are being expanded.
2006-09-15 06:05:17 · 16 answers · asked by 2112 1 in Science & Mathematics ➔ Mathematics
You need to remember your order of operations...
Please Excuse My Dear Aunt Sally
OMG people -- it's been solved. Point whores.
2006-09-15 06:07:09 · answer #1 · answered by Anonymous · 2⤊ 3⤋
Remember that multiplications can be done in any order, unlike additions or subtractions. So you can do this in a couple of ways. Either multiply by the first bracket out by 2 and then multiply that by the second bracket:
(2x+1)(x-3)
2x^2 - 5x -3
Or multiply the brackets together then multiply the whole thing by 2:
2(x^2 - 2.5x - 1.5)
2x^2 - 5x -3
2006-09-15 06:15:00 · answer #2 · answered by Anonymous · 1⤊ 0⤋
Heard of the BODMAS rule?? In solving an equation you always need to remember this rule. BODMAS is the sequence of operations you must follow while solving any algebraic equation. Brackets Off.. Division.. Multiplication.. Addition.. Subtraction.
This will help you decide the priority of any operation.
so.. in the equation 2(x+0.5)(x-3)
you will first remove the existing brackets
you will get,
2(x^2-2.5x-1.5)
the digit 2 on the outside of the bracket indicates that 2 is multiplied to the entire equation inside the bracket.
so when you remove the brackets, u get,
2x^2-5x-3.
2006-09-15 06:14:30 · answer #3 · answered by noesis 2 · 1⤊ 0⤋
you need to multiply everything in the first bracket by 2, this gives (2x+1). Now multiply everything in the first bracket (2x+1) by everything in the second bracket (x-3) , so....2x multiplied by x = 2x^2 (thats 2x squared) 2x multiplied by -3 = -6x , then, 1 multipled by x = x , and 1 multipled by -3 = -3. When you add the answers together ( 2x^2 + -6x + x + -3) this gives 2x^2 - 5x -3. I hope this helps
Rachel
2006-09-16 08:50:01 · answer #4 · answered by Rach H 1 · 0⤊ 0⤋
The answer is 2x^2-5x-3
2(x+0.5)(x-3) =
2(x^2-3x+0.5x-1.5) =
2(x^2-2.5x-1.5)
= 2x^2-5x-3
Multiply out the brackets before dealing with the numbers outside the brackets.
2006-09-17 08:13:27 · answer #5 · answered by Ken B 2 · 0⤊ 0⤋
You have two options, either distribute the 2 to either bracket, or use the FOIL method fist and then multiply by two. Since multiplication is a process whose sum is irrespective of order (a x b x c = b x c x a) then use whichever method is easiest for you.
2(x + 0.5)(x - 3) = (2x + 1)(x - 3) = 2x^2 - 5x - 3
Something I like to do is convert all of my minus signs to plus signs and add the opposite, e.g. x - 4 = x + (- 4). The reason that I do this is that it's easier (for me) to keep the signs correct when distributing terms.
2006-09-15 06:14:04 · answer #6 · answered by L96vette 5 · 0⤊ 1⤋
Well you could either multiply the brackets out and then multiply by two, or easier, multiply the first bracket by two, then expand.
(2x+1)(x-3)
=2x^2-5x-3
2006-09-15 06:09:49 · answer #7 · answered by Mr Glenn 5 · 3⤊ 0⤋
Just multiply it in the order it comes from left to right.
in the first bracket you get (2x + 1)
Then multiply (2x + 1) and (x - 3)
2x^2 - 6x + 1x - 3
then join like terms and you get
2x^2 - 5x - 3
2006-09-15 06:16:40 · answer #8 · answered by MissHealthPromoter 3 · 1⤊ 0⤋
When expanding brackets, you multiply everything in the brackets
by the number to the left of it. So in this case it would become 2x+1(x-3). Then you would need to expand the second bracket, making the problem 2x+x-3.
Hope that helped.
2006-09-15 06:08:20 · answer #9 · answered by Sophie P 2 · 2⤊ 4⤋
2(x+0.5)(x-3)
= 2(x^2 - 3x + 0.5x - 1.5)
= 2x^2 - 6x + x - 3
= 2x^2 - 5x - 3
OR
(2x+1)(x-3)
= 2x^2 - 6x + x -3
= 2x^2 - 5x - 3
Just treat it in the same way as: 2x3x4=2x(3x4)=(2x3)x4
You can multiply the first 2 or the last 2 first. It doesn't make a difference.
2006-09-16 05:49:33 · answer #10 · answered by Kemmy 6 · 0⤊ 0⤋
2(x+0.5)(x-3)
= 2(x²+0.5x-3x-2.5)
=2(x²-2.5x-2.5)
=2x²-5x-5
It's Friday at 6:15. Not the time for maths.
2006-09-15 06:17:13 · answer #11 · answered by k² 6 · 0⤊ 1⤋