(4x - 7)(3x + 1)?

(4x - 7)(3x + 1) = 12x²+4x-21x-7
= 12x²-17x-7

(4x - 7)(3x + 1) = 12x²+4x-21x-7
= 12x²-17x-7
17x=12x²-7
17= (12x²-7)/x
17= 12x-(7/x)
17x=12x-7
17x-12x=-7
5x=-7
x=-7/5

take 4x multiplied by 3x which equals 12x squared then take 4x times 1 which equals 4x then take the -7 multiplied by 3x which equals -21x then multiply -7 times 1 which equals -7

which looks like 12xsquared + 4x -21x -7
add the x's which equals 17x

the answer= 12(squared) -17x -7

12x^2 +4x -21x -7 and you add it up