Respuesta :

5 because if you plug in to get the equation 3x+20=7x then subtract 3x from both sides and divide by 4 from both sides

Answer:

x =5 is the answer

Step-by-step explanation:

m =7x

m =3x+20 , it will be solved  by substituting   method  

substituting m=7x in m=3x+20

 7x =3x+20

7x-3x =20

4x =20

divide by 4 ,we get

x =5