First you want to write 7x as a sum or difference: 15x-8x
Now, the expression would look like this: 10x^2+15x-8x-12
Next, factor out the 5x and -4 from the expression: 5x(2x+3)-4(2x+3)
Now, factor out the 2x+3 from the expression and you have your answer:
(2x+3)(5x-4)
I think it's 5, I made a paper airplane and counted.
Use the identity:
tan^2 = sec^2 - 1
I attached a photo showing all the steps including the final answer.
The answer is 0.6144÷1.6 =0.384
hope i help solving your question.