There seems to be an error in the last expression. Looking at the problem as a whole, it’s an equation, not just an expression to be simplified. An equation means either an identity that needs to be proved, or an equation with a variable that needs to be solved for that variable.
Nevertheless, I can offer some help. The first multiplier on the right-hand side simplifies to (7r-3)/(2r-3)² if we assume that the division stroke (/) implies that the expressions on either side of it are grouped as a single entity. That being the case, the common denominator r²-1 cancels out and 4r²-12r+9 is the perfect square of 2r-3.
The second multiplier numerator factorises: (r+1)(2r-3), so 2r-3 divides into the denominator of the other multiplier, making it (7r-3)/(2r-3). The denominator of the second multiplier looks wrong, and it could be 3r²-2r-1 which factorises: (3r+1)(r-1), or it could be 3r²+2r-1, factorised as (3r-1)(r+1). Note that r+1 is also a factor in the numerator, so it would cancel it out.
The final part of this is the left-hand side 6r². Although the right-hand side can be simplified, it doesn’t make it easy to solve for r, so the question arises: should the equals sign be an operator such as +, -, ×, ÷?
Please check that you have copied the question accurately and asked the right question. You may be able to solve the problem yourself given the partial details above.