Please help with math

Scale factor  = 3

Step-by-step explanation:

Using similar triangles

AT/AG = AB/AC

9/3 = x+10/3x-10

Cross multiply

3(x+10) = 9(3x-10)

Expand

3x+30 = 27x-90

3x-27x = -90 - 30

-24x = -120

x = 120/24

x = 5

For the larger triangle;

AC = 3x-10

AC = 3(5)-10

AC =15-10

AC = 5

AB = x+10

AB = 5+10

AB = 15

For the scale factor;

Since AT/AG = AB/AC

9/15 = 3/5

3*3/5*3 =3/5

Since the numerator and denominator of the larger triangle is multiplies by the same factor i.3 3. Hence the scale factor is 3