Question

the lines 2ax+by =5 and ax+2by=4 intersect at the point (1,2) what is the value of a and b

Answer 1

Here is your answer;

2ax+by=5 and ax+2by=4 intersect at (1,2)

So,the points (1,2) are X,Y

Substitute them in the above two equations

then we get

2a(1)+b(2)=5 => 2à+2b=5

a(1)+2b(2)=4. =>a+4b=4

Now solve both equations.You can solve it in many methods .I am solving in elimination method.

2a+2b=5

2(a+4b=4)

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-6b=-3

=>b=1/2

substitute b in one of the equation

2a+2(1/2)=5

2a+1=5

=>a=2

the values a=2

b=1/2