What is the value of the modulus of 6−4i ?
Enter your answer as a simplified radical
The modulus of complex number a + bi is sqrt( a2+ b2 )..
The modulus of 6 - 4i is sqrt( 62 + (-4)2 ) = sqrt( 36 + 16 ) = sqrt( 52 ).
I'll leave it to you to place it into reduced radical form ...