Answer:
1 - 2√7
Step-by-step explanation:
( 4 + √7)(2 - √7)
Open the brackets with
( 4+ √7)
= 4( 2 - √7) + √7(2 - √7)
= 8 - 4√7 + 2√7 - √49
= 8 ( -4 + 2)√7 - √49
= 8 - 2√7 - 7
= 8 - 7 - 2√7
= 1 - 2√7