1) x^2-11x+30 2) x^2-21x+110 3) 4x^2-64 4) 4x^2-2x-0.75 - вопрос №35737151211302221110342644422075 от nikitame6 28.10.2020 11:19

Question

Алгебра: 1) x^2-11x+30 2) x^2-21x+110 3) 4x^2-64 4) 4x^2-2x-0.75 )заранее

nikitame6 · Answer

1) x^2-11x+30=(x-5)(x-6) 2) x^2-21x+110=(x-10)(x-11)
3) 4x^2-64=4(x²-16)=4(x²-4²)=4(x-4)(x+4)
4) 4x^2-2x-0.75=4(x+0.25)(x-0.75)
D = b2 - 4ac = (-2)2 - 4·4·(-0.75) = 4 + 12 = 16
x= $\frac{2+- \sqrt{16} }{8}= \frac{2+-4}{8}$
x1=0.75
x2=-0.25