Please help with these 3 pretty easy problems and explain how you got it Serious answers please..

Step-by-step explanation:

1)

(x-3)/18=12/9, cross multiply

9(x-3)=18(12)

9x-27=216, add 27 to each side

9x=243, divide each side by 9

x=27

2)

(x-16)/(x+6)=3/5, cross multiply

5(x-16)=3(x+6)

5x-80=3x+18, subtract 3x from each side

2x-80=18, add 80 to each side

2x=98, divide each side by 2

x=49

3)

Since the triangles are similar we can say that

25/(4x-1)=10/(x+5), cross multiply

25(x+5)=10(4x-1)

25x+125=40x-10, subtract 40x from each side

-15x+125=-10, subtract 125 from each side

-15x=-135, divide each side by -15

x=9

the answer is b. 60. each interior angle in 120, so the exterior angle must be 60 in order to add up to 180

step-by-step explanation: