Question

$(2x -7) {}^{2} - 11(2x - 7) + 30 = 0$

Answer 1

4x^2-28x+49-22x+77+30=0
4x^2-50x+156=0 | поделим все на 2
2x^2-25x+78=0
D=625-4*2*78=625-624=1
x1=-b+√D/2a=25+1/2*2=6.5
x2=-b-√D/2a=25-1/2*2=6