Please help me, I will give brainliest, 5 stars and thanks to anyone that answers correctly :) This football pitch has an area of 7140m²

Show that 12x² - 13x - 7175 = 0

Please be sure to explain your answer, I'd like to understand how you got to the answer so that I'll be able to answer similar questions in the future :)

12x^2 -13x - 7175 = 0.

Step-by-step explanation:

what I did was (4x+5)(3x-7) = 7140

Then I expanded it (so 12x^2 +15x - 35 -28x = 7140)

I then took away 7140 from both sides to have a quadratic equation to solve

28%

Step-by-step explanation:

Lets say the fraction of speed and problem solved is 100/100

the number of problems solved increases by 60%

so now it is 160/100, also the speed increases by 25%

so now we do 160/125=1.28

finaly we do 1.28-1 = 28%

Therefore the answer is 28%.

hope this helps