Answer:
3x
Step-by-step explanation:
givens: x=4
now try your options:
3(4)+3=15
12+3=15
15=15
The first option is correct, therefore the answer is 3x
19.8 rounded to 1 s.f. is
20
The equation is 
The solved equation is 11
First, we must add 13 on both sides
The answer to the equation is
Express √3 + i in polar form:
|√3 + i| = √((√3)² + 1²) = √4 = 2
arg(√3 + i) = arctan(1/√3) = π/6
Then
√3 + i = 2 (cos(π/6) + i sin(π/6))
By DeMoivre's theorem,
(√3 + i)³ = (2 (cos(π/6) + i sin(π/6)))³
… = 2³ (cos(3 • π/6) + i sin(3 • π/6))
… = 8 (cos(π/2) + i sin(π/2))
… = 8i
In the problem -5+x=0, x=5
