We can think of this as an equality
5 Lawns = 8 Hours
If she needs 40 hours, you can multiply 8 hours by 5 to get 40, but now it's not balanced. So, you need to multiply 5 to the other side too so:
5 x (5) = 8 x (5)
Therefore she mows 25 Lawns in 40 Hours
Just multiply them so first multiply 2.7 times .9 and then times your answer by .6
13. (a-b)^2=a^2-2ab+b^2
B is the answer
14. B is the answer
( x+9)(x-3)= x^2+6x-27
15. B is the answer
(x+6)(x-5)=x^2+x-30
16. D is the answer
(x-6y)(x-4y)=x^2-10xy+24y^2
17. C is the answer
(2x+5)(3x-4)=6x^2+7x-20
18. B is the answer
(5x+7)(x-2)=5x^2-3x-14
Use a calculator called symbolab.com 0-0