因式分解1+10t+25t^2m^2-14m+19y^2+y+1/4(m+n)^2-4m(m+n)+4m^225a^2-80a+64a^2+2a(b+c)+(b+c)^221*3.14+62*3.14+17*3.14758^2-258^2..

Question

因式分解
1+10t+25t^2
m^2-14m+19
y^2+y+1/4
(m+n)^2-4m(m+n)+4m^2
25a^2-80a+64
a^2+2a(b+c)+(b+c)^2
21*3.14+62*3.14+17*3.14
758^2-258^2
..

Answer 1

1+10t+25t^2 = (5t + 1)^2
m^2-14m+19（打错了?其他都是平方,这是49?） = (m-7)^2
y^2+y+1/4 = (y + 1/2)^2
(m+n)^2-4m(m+n)+4m^2 = (m+n + 2m)^2 = (3m + n)^2
25a^2-80a+64 = (5a-8)^2
a^2+2a(b+c)+(b+c)^2 = (a + b + c)^2
21*3.14+62*3.14+17*3.14 = 3.14(21 + 62 + 17) = 3.14*100 = 314
758^2-258^2 = (758+258)(758-258) = 500(1016) = 508000