Vectors

posted by annonymous

if a=3x+2y and b=5x-4y, find x and y in terms of a and b

What I did:
2a=6x+4y
+b=5x-4y
---------
2a+b=x
2(3x+2y)+(5x-4y)=x
6x+4y+5x-4y=x
11x=x
11x dvided by x = 11

...that isn't the correct answer. The correct answer (according to text book) is
x=2/11a+1/11b
y=5/22a-3/22b

I'm puzzled on how to do this with all the letters. I also don't know how to find out y. I think I did a bit of figuring for x right, right?

1. Reiny

2a = 6x + 4y
b = 5x - 4y
2a + b = 11x
x = (2a+b)/11 or 2a/11 + b/11 , which is the given answer

now plug the x back into the first equation:
5x - 4y = b
5(2a+b)/11 - 4y = b
times 11
5(2a + b) - 44y = 11b
10a + 5b - 44y = 11b
-44y = -10a + 6b
y = (-10a + 6b)/-44
= (5a - 3b)/22 , which is the same as the given y

Similar Questions

1. Algebra

3x-27/55÷x-9/15x my answer is =3(11x^2-4)/11x is this correct.
2. Algebra 1

3x-27/55÷x-9/15x my answer is =3(11x^2-4)/11x is this correct.
3. algebra

Can anyone tell me if I got this problem right 12x-6=11x 12x-6+6=11x+6 12x-11x=6 1x=6 x=6/1 x=6 Yes, that is correct
4. Algebra

3x-27/55÷x-9/15x my answer is =3(11x^2-4)/11x is this correct
5. math

I solved this problem 12x-6=11x -6+6=0 11x+6 12x=11x+6 12x-11x=x 11x-11x=0 x=6 Can someone show me the process of checking it?
6. Algebra

I need to make sure this is correct. 5/2x+1/4x=11/4+x 4(5/2x+1/4x=11/4+x) cancel, left with 10x+1x=11+x 11x=11+x 11x-x=11 10x=11 x=11/10
7. math

please help me out here the problem is combining like terms. 4x^3-3x^3+9x+2x I got 1x^3+11x but when i asked a friend they said it would be x^3+11x could u help me out please. also could you tell me if this probem is correct as well …
8. Math

Okay, this isn't really a big question. I know how to do it, there's just one thing I have to make sure of. The problem is: 5x+4y-11x-2y I know I need to combine like terms, but which sign do I use to do that. Like if I want to combine …
9. Algebra 1b!

1. Find the excluded value of x for the polynomomial expression 4x/6 a. 6 b. -6 c. 1/6 d. -1/6 2. Simplifly 3-2x/7 + 4x+5/7 a. 2x+8/14 b. 2x+8/7 <--- c. x+1/7 d. 2x+2/7 3. Simplify 6ab^6/4a^7b^10 * a^3b^4/2a^7b^6 a. 7x/8 - 2x/8 …
10. Calculus

I've done everything I can think of to solve this, but I have no idea. Find the derivative: y = sq rt{11x + sqrt[11x + sqrt(11x)]}

More Similar Questions