(15-7)(7+15)
Apply the distributive property.
15(7+15)-7(7+15)
Apply the distributive property.
15⋅7+1515-7(7+15)
Apply the distributive property.
15⋅7+1515-7⋅7-715
15⋅7+1515-7⋅7-715
Simplify each term.
Move 7 to the left of 15.
7⋅15+1515-7⋅7-715
Combine using the product rule for radicals.
715+15⋅15-7⋅7-715
Multiply 15 by 15.
715+225-7⋅7-715
Rewrite 225 as 152.
715+152-7⋅7-715
Pull terms out from under the radical, assuming positive real numbers.
715+15-7⋅7-715
Multiply -7 by 7.
715+15-49-715
715+15-49-715
Subtract 715 from 715.
0+15-49
Add 0 and 15.
15-49
Subtract 49 from 15.
-34
-34
Multiply ( square root of 15-7)(7+ square root of 15)
