# A triangle has sides of length (x+5)cm, (2x -1) cm and (3x+7) cm. How do you find the value of x given the perimeter of the triangle is 29cm?

Nov 28, 2016

$x = 3$

#### Explanation:

We get the perimeter of the triangle by adding up the length of all the sides:

$\therefore \left(x + 5\right) + \left(2 x - 1\right) + \left(3 x + 7\right) = 29$
$\therefore x + 2 x + 3 x + 5 - 1 + 7 = 29$
$\therefore 6 x + 11 = 29$
$\therefore 6 x = 18$
$\therefore x = 3$

So the lengths would be:

$x + 5 = 8$
$2 x - 1 = 5$
$3 x + 7 = 16$

Total $= 29$