Find a polynomial with real coefficients that has the given zeros. -1 and 5-2i.
P(x)= (x+1)[x-(5-2i)][x-(5+2i)]
P(x)= (x+1)[(x-5)^2-(2i)^2]
My 'help me solve this' jumps to...
P(x)= (x+1)[x^2-10x+25+4]
My question is how are they getting that expression within the brackets? I keep getting stuck on that. I have this feeling it's really obvious. :/
P(x)= (x+1)[x-(5-2i)][x-(5+2i)]
P(x)= (x+1)[(x-5)^2-(2i)^2]
My 'help me solve this' jumps to...
P(x)= (x+1)[x^2-10x+25+4]
My question is how are they getting that expression within the brackets? I keep getting stuck on that. I have this feeling it's really obvious. :/