Question

William says that 15 years from now, his age will be 3 times his age 5 years ago. If x represents William’s present age, complete the following sentences. 15 years18 yearsx − 15 = 3(x + 5)x + 15 = 3(x − 5)

Answer 1

William's present age = x
William 15 years from now = x + 15
William 5 years ago = x - 5

William says that 15 years from now, his age will be 3 times his age 5 years ago. 
x + 15 = 3(x-5)  ← equation formed
x + 15 = 3x - 15
3x - x = 15 + 15
2x = 30
x = 15 . ← William's current age
William is 15 now

Answer 2

Answer:

As per the statement:

William says that 15 years from now, his age will be 3 times his age 5 years ago.

Here, x represents the  William’s present age.

"His age after 15 years from now means"  x +15

"His age 5 years ago means x -5"

"3 times his age 5 years ago translated to" 3 (x-5)

then;

the statement becomes:

$x+15 = 3(x-5)$

Using distributive property $a \cdot (b+c) =a\cdot b+ a\cdot c$

$x+15 = 3x-15$

Subtract x from both sides we have;

$15 = 2x-15$

Add 15 to both sides we have;

$30 = 2x$

or

2x = 30

Divide both sides by 2 we have;

x = 15

Therefore, the present age of William’s is, 15 years