Answer:
x2+11x+28
Explanation:
We have two binomials, so we can use the highly useful mnemonic FOIL to helps us: 
 
Multiply the first terms: 
x 
⋅ 
x 
= 
x 
2 
Multiply the outside terms: 
x 
⋅ 
4 
= 
4 
x 
Multiply the inside terms: 
7 
⋅ 
x 
= 
7 
x 
Multiply the last terms: 
7 
⋅ 
4 
= 
28 
Thus, 
( 
x 
+ 
7 
) 
( 
x 
+ 
4 
) 
 multiplies out to 
x 
2 
+ 
4 
x 
+ 
7 
x 
+ 
28 
, which can be simplified to: 
 x 2 +11 x + 28
Hope this helps!