Help with maths please...?

(5-2√7)(√7+2) =

5√7+ 10 - 14 - 4√7=

√7 - 4

(5 - 2√7)(√7 + 2)
= 5(√7) + 5(2) - 2√7(√7) - 2√7(2)
= 5√7 + 10 - 2(7) - 4√7
= 10 - 14 + 5√7 - 4√7
= -4 + √7

multiply the terms..
we get, sqrt(7)-4

First, times the first number in the first set of brackets by both numbers in the second set of brackets.

5 * √7 = 5√7
5 * 2 = 10

Next, times the second number in the first set of brackets by both numbers in the second set of brackets.

-2√7 * √7 = -2 * √7 * √7 = -2 * 7 = -14
-2√7 * 2 = -4√7

So your answer is:

5√7 + 10 - 14 - 4√7

This can be simplified:

√7 - 4

You would normally leave this as it is, in its "surd form", but it can be further evaluated to get -1.354 to three decimal places.

=5\/''7'''' +10 -14 -4\/''''7'''''=\/'''7''''' -4
God bless you.

(5-2root7)(root7+2)
=> 5(root7+2)-2root7(root7+2)
=> 5root7+10-14-4root7
=> root7-4

5√7 + 10 - 14 - 4√7 = √7 - 4

(5-2√7)(√7+2)
=5√7 + 10 - 2x√7x√7 - 4√7
=√7(5-4) + 10 - 2x7
=√7 + 10 - 14
=2.646 + 10 - 14
= -1.354