Question 1057502
(a)
{{{ ( 2 + i ) - sqrt(-64) }}}
{{{ ( 2 + i ) - sqrt(64)*sqrt(-1) }}}
{{{ ( 2 + i ) - 8i }}}
{{{ 2 - 7i }}}
-----------------------
(b)
{{{ -4*i^13 + 7*i^6 }}}
( note that {{{ i^2 = -1 }}} and {{{ i^4 = 1 }}} )
{{{ -4*( i^4)^3*i + 7*( i^4 )*i^2 }}}
{{{ -4*1^3*i + 7*1*(-1) }}}
{{{ -4i - 7 }}}
{{{ -7 - 4i }}}
--------------------
(c)
{{{ ( 4 - i )*( 3 + 5i ) }}}
{{{ 12 - 3i + 20i - 5*i^2 }}}
{{{ 12 + 17i - 5*(-1) }}}
{{{ 12 + 5 + 17i }}}
{{{ 17 + 17i }}}
-------------------------
You might want a 2nd opinion on these
check my work