Solve for m algebra help

let x=m+3
solve 4(m+3)^2-13(m+3)-35=0
solve for m

4(m+3)^2 - 13(m+3) - 35 = 0
Let x = m+3
then
4x^2 - 13x - 35 = 0
==> (4x +7)(x-5) = 0
==> x = -7/4 or x = 5
so
m+3 = -7/4 or m+3 = 5
==> m = -19/4 or m = 2

4(m+3)²-13(m+3)-35 = 0 = 4x²-13x-35
Let ax²+bx+c = 0
Then x = [-b±√(b²-4ac)]/2a
x = [13±√(169+560)]/8
x = [13±27]/8 = 5, -7/4
Check: 4(5)²-13(5)-35 = 100-65-35 = 0
4(-7/4)²-13(-7/4)-35 = 4×49/16+91/4-35 = 0

4x^2-13x-35 = 0
(4x+7)(x-5) = 0
x = 5 or -7/4
m = 2 or -19/4