Question

ex 18 va rog.
Dau coroana
​

Answer 1

a)

(a - b)² + 2 · 5 · (a - b)(c + d) + 25(c + d)² =

= [(a - b) + 5(c + d)]² =

= (a - b + 5c + 5d)²

b)

(x - a)² + 2(x - a)(y + b) + (y + b)² =

= [(x - a) + (y + b)]² =

= (x - a + y + b)²

c)

(x + y)² + 6(x + y)(x - y) + 9(x - y)² =

= [(x + y) + 3(x - y)]² =

= (x + y + 3x - 3y)² =

= (4x - 2y)²

d)

(x + 2)² - 2(x + 2)(y - 3) + (y - 3)² =

= [(x + 2) - (y - 3)]² =

= (x + 2 - y + 3)² =

= (x - y + 5)²

e)

(a + √2x)² - 4(a² - 2x²) + 4(a - √2x)² =

= (a + √2x)² - 4(a + √2x)(a - √2x) + 4(a - √2x)² =

= [(a + √2x) - 2(a - √2x)]² =

= (a + √2x - 2a + 2√2x)² =

= (3√2x - a)²