Let z=x+iy, where x and y are real numbers. Then the complex conjugate of z is z=x−iy. Substitute z=x+iy and z=x−iy into the equation: 2(x+iy)−(1+i)(x−iy)=−1+5i 2x+2iy−(x−iy+ix−i2y)=−1+5i Since i2=−1, we have: 2x+2iy−(x−iy+ix+y)=−1+5i 2x+2iy−x+iy−ix−y=−1+5i (2x−x−y)+(2y+y−x)i=−1+5i (x−y)+(3y−x)i=−1+5i Now, equate the real and imaginary parts:
We now have a system of two linear equations with two variables:
x−y=−1 (1) −x+3y=5 (2) Adding equations (1) and (2), we get:
x−y−x+3y=−1+5 Substitute y=2 into equation (1): Therefore, z=x+iy=1+2i.