Question

a) (x + 2)²

b) (2x + y)²

c) (x - 3y)²

d) (1/2x - y)²

e) (x² - y)²

 

 

Answer 1

a: \(\left(x+2\right)^2=x^2+2\cdot x\cdot2+2^2=x^2+4x+4\)

b: \(\left(2x+y\right)^2=\left(2x\right)^2+2\cdot2x\cdot y+y^2=4x^2+4xy+y^2\)

c: \(\left(x-3y\right)^2=x^2-2\cdot x\cdot3y+\left(3y\right)^2=x^2-6xy+9y^2\)

d: \(\left(\dfrac{1}{2}x-y\right)^2=\left(\dfrac{1}{2}x\right)^2-2\cdot\dfrac{1}{2}x\cdot y+y^2\)

\(=\dfrac{1}{4}x^2-xy+y^2\)

e: \(\left(x^2-y\right)^2=\left(x^2\right)^2-2\cdot x^2y+y^2=x^4-2x^2y+y^2\)

Answer 2

a) \(\left(x+2\right)^2\)

\(=x^2+2\cdot x\cdot2+2^2\)

\(=x^2+4x+4\)

b) \(\left(2x+y\right)^2\)

\(=\left(2x\right)^2+2\cdot2x\cdot y+y^2\)

\(=4x^2+4xy+y^2\)

c) \(\left(x-3y\right)^2\)

\(=x^2-2\cdot x\cdot3y+\left(3y\right)^2\)

\(=x^2-6xy+9y^2\)

d) \(\left(\dfrac{1}{2}x-y\right)^2\)

\(=\left(\dfrac{1}{2}x\right)^2-2\cdot\dfrac{1}{2}x\cdot y+y^2\)

\(=\dfrac{x^2}{4}-xy+y^2\)

e) \(\left(x^2-y\right)^2\)

\(=\left(x^2\right)^2-2\cdot x^2\cdot y+y^2\)

\(=x^4-2x^2y+y^2\)

Answer 3

a)(x+2)²=x²+2×x×2+2²=x²+4x+2

b)(2x+y)²=(2x)²+2×2x×y+y²=4x²+4xy+y²

c)(x-3y)²=x²-2×x×3y+(3y)²=x²-6xy+9y

d)(1/2x-y)²=(1/2x)²-2×1/2x×y+y²=1/4x²-xy+y²

e)(x²-y)²=(x²)²-2×x²×y+y²=x⁴-2x²y+y²