Question

2(ax-by)+a+4b=0
2(bx+ay)+b-4a=0
find value of x & y by cross multiplication

Answer 1

pl solve my problem

Answer 2

i get
\[x=-\frac{1}{2}\]

Answer 3

\[(2ax-by)=-a-4b\]
\[a(bx+ay)=4a-b\]

Answer 4

multiply the first equation by b, the second one by a get
\[2(a^2x-aby)=-a^2-4ab\]
\[2(b^x+aby)=4ab-b^2\]

Answer 5

ok lots of typos here but the idea is correct second line above should be
\[2(b^2x +aby)=4ab-b^2\]

Answer 6

now add first and second equation to get
\[2(a^2+b^2)x=-a^2-b^2\]
\[2(a^2+b^2)x=-(a^2+b^2)\]
\[x=-\frac{a^2+b^2}{2(a^2+b^2)}=-\frac{1}{2}\]

Answer 7

assuming of course that a and b are not both zero.

Answer 8

and assuming that you come back and check this question

Answer 9

x -y 1
------------------- = ----------------- = ---------------
-2b(b-4a) - 2a(a+4b) 2a(b-4a)-2b(a+4b) 2a.2a - 2b.-2b

Answer 10

Solve both sides for x & then set equal to each other to end with y = 2.
Substitute 2 in for y in either equation and you should get x = -1/2