The difference of two squares. The number which, when multiplied together three times yields the original number.
Answer:
C
Step-by-step explanation:
In this technique, if we have to factorise an expression like ax2+bx+c, we need to think of 2 numbers such that:
N1⋅N2=a⋅c=1⋅−12=−12
AND
N1+N2=b=−1
After trying out a few numbers we get N1=3 and N2=−4
3⋅−4=−12, and 3+(−4)=−1
x2−x−12=x2−4x+3x−12
x(x−4)+3(x−4)=0
(x+3)(x−4)=0
Now we equate the factors to zero.
x+3=0,x=−3
x−4=0,x=4
(2 − 3i) + (x + yi) = 6
We add the left hand side
(2+x) + (-3+y)i = 6
6 can be written in a+ib
6 can be written as 6 + 0i
(2+x) + (-3+y)i = 6 +0i
Now we frame 2 equations
2 + x= 6
-3 + y =0
Solve the first equation
2 + x = 6
Subtract 2 from both sides
x = 4
solve the second equation
-3 + y =0
Add 3 on both sides
y= 3
So x+yi is 4+3i