The length of a rectangular field is 5x^2-6x-1 and its width is x^2+7x-3.find the area of the field. use this formula to solve : a=l*w

Basically, multiply them

this is frightnening to some
remember that (x^m)(x^n)=x^(m+n)
so x^2 times x=x^3 and x^2 times x^2=x^4

just keep distributing
so
(a+b+c)(d+e+f)=a(d+e+f)+b(d+e+f)+c(d+e+f)=ad+ae+af+bd+be+bf+cd+ce+cf

do that

(5x²-6x-1)(x²+7x-3)=
(5x²)(x²+7x-3)+(-6x)(x²+7x-3)+(-1)(x²+7x-3)=
(5x⁴+35x³-15x²)+(-6x³-42x²+18x)+(-x²-7x+3)=
5x⁴+35x³-15x²-6x³-42x²+18x+-x²-7x+3=
5x⁴+35x³-6x³-15x²-42x²-x²+18x-7x+3=
5x⁴+29x³-58x²+11x+3

the area is 5x⁴+29x³-58x²+11x+3