Solve it how?

Solve for what?

Let me make a guess.

Since this is in Geometry, you want to know what is the graph of that thing, that equation.

Okay, let me work it on that guess.

1/3x+3/4y=4

I bet that is

(1/3)x +(3/4)y = 4.

First we clear the fractions,

Multiply both sides of the equation by the product of the denominators of the two fractions, which are 3 and 4,

Multiply both sides by 3*4,

4*1*x +3*3*y = 4*3*4

4x +9y = 48 -----(i)

(It is a straight line.)

Convert that Eq.(i) into y = mx +b,

9y = -4x +48

y = -(4/9)x +48/9

y = -(4/9)x +16/3 ----(ii)

So,

It is a straight line whose slope is -4/9, and whose y-intercept is 16/3.

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It is only my guess, remember.