$\bf \textit{difference of squares}
\\\\
(a-b)(a+b) = a^2-b^2\qquad \qquad 
a^2-b^2 = (a-b)(a+b)
\\\\\\
\textit{also recall that }i^2=-1\\\\
-------------------------------\\\\
\begin{cases}
x=-1+4i\implies &x+1-4i=0\\
x=-1-4i\implies &x+1+4i=0
\end{cases}
\\\\\\
(x+1-4i)(x+1+4i)=\stackrel{y}{0}
\\\\\\\
[(x+1)~~-~~(4i)][(x+1)~~+~~(4i)]=y
\\\\\\\
[(x+1)^2~~-~~(4i)^2]=0\implies (x^2+2x+1)~-~(4^2i^2)=y
\\\\\\
(x^2+2x+1)~-~(16\cdot -1)=y\implies (x^2+2x+1)~-~(-16)=y
\\\\\\
x^2+2x+1~~+16=y\implies x^2+2x+17=y$

3 0

3 years ago

2(3x−5a)+9(2a−7b)+3(5a−2x)=0

alexdok [17]

Answer:

a=63b/23, b=23a/63

7 0

2 years ago

Write an expression that is equivalent to 2/3(4x + 9). (4 points) Select one: a. 8/3x + 6 b. 8/3x + 9 c. 2/3x + 6 d. 2/3x + 9

Lady_Fox [76]

You have to distribute the 2/3 across the equation.

8/3x+18/3 which is 8/3x+6 so the answer is a

I hope that helps

3 0

3 years ago