Question

Proszę o pomoc. Zadania w załącznikach.

Answer 1

4.15
a) (x+3y)(x-3y)+(x+2y)²-(2x²-5y²)=x²-3²+x²+4xy+4y²-2x²+5y²=9y²+4xy-9
9*(√2)²+4*√8*√2-9=9*2+4√16-9=18+4*4-9=18+16-9=25
c)(x+2y)(x-2y)-4x(x-y)+(x-2y)²+4xy=x²-(2y)²-4x²+4xy+x²-4xy+(2y)²+4xy=-2x²+4xy-4y²+4y²=-2x²+4xy
-2(0,5)²+4*0,5*(-0,5)=-2*0,25-1=-0,5-1=-1,5
4.11
e) (5a+1)²+(5a-1)²-(5a+1)(5a-1)-25a²=(5a)²+10a+1+(5a)²-10a+1-[(5a)²-1²]-25a²=25a²+2+25a²-(25a²-1)=50a²+2-25a²+1=25a²+3
f)(x+3y)(3y-x)-2(x-2)²+3(x²-3y²)=-(-x-3y)(-x+3y)-2(x²-4x+4)+3x²-9y²=-[(-x)²-(3y)²]-2x²+8x-8+3x²-9y²=-(x²-9y²)+x²+8x-9y²-8=-x²+9y²+x²+8x-9y²-8=8x-8