Precalculus: Mathematics for Calculus, 7th Edition

$(7-i)(4+2i)$ = $30+10i$
1. $(7-i)(4+2i)$ 2. Multiply the two binomials together (use the FOIL method and distribute the First, Outer, Inner, and Last terms): $28+14i-4i-2i^{2}$ 3. Combine like terms: $-2i^{2}+10i+28$ 4. Simplify $-2i^{2}$ to 2, because $i^{2}$ = -1, and $-2\times-1 = 2$: $2+10i+28$ 5. Combine like terms: $30+10i$