Question

Oblicz:

a) (3/4a - 4/5y)²
b) (ab-3/4y)²=

c)(2x-0,3)²=

d) (1/3a -6b)(1/3a+6b)=

e)(5x +y)(5x-y)=

f)2(√2-5)² - 3(√2 +3)²

g)(√2+3)(√2-3)(√2+3)²

Answer 1

korzystamy ze wzorów skróconego mnożenia

a) (3/4a - 4/5y)²=

= 9/16a² - 2*3/4a*4/5y + 16/25 y²=

=9/16a²- 24/20ay + 16/25y²=

=9/16a² - 6/5ay + 16/25y²=

=9/16a² - 1 i 1/5ay + 16/25y²

 

b)(ab-3/4y)²=

=a²b²-2*3/4y*ab+9/16y²=

=a²b²-6/4aby+9/16y²=

=a²b²-1 1/2aby+9/16y²

 

c) (2x-0,3)²=

=4x²-1,2x+0,09

 

d) (1/3a-6b)(1/3a+6b)=

=1/9a²-36b²

 

e) (5x+y)(5x-y)=

=25x²-y²

 

f) 2(√2-5)²-3(√2+3)²=

=2(2-10√2+25)-3(2+6√2+9)=

=4-20√2+50-6-18√2-27=

=21-38√2

 

g) (√2+3)(√2-3)(√2+3)²=

=(2-9)(2+6√2+9)=

=-7(6√2+11)=

=-42√2-77