Roberto wrote a sentence that describes an equation.
Half of a number is 45.
Which choice shows Roberto's equation and its solution?
2x=45; X = 90
45/2= x; x= 22.5

X/2=45; X= 22.5
X/2=45; x= 90

The last one: x/2=45; x = 90
the problem says: half of a number is 45.

let's use x to represent this number
we know that dividing by 2 halves a number, so, x/2 = 45

to get x alone, we multiply 2 by 2 to cancel it out. so, multiply by 2 on both sides

x/2 • 2 = 45 • 2

x = 90

hope this helped!