2(x+7) + x=20
(2)(x) + (2)(7) + x=20 Distribute
2x+14 + x =20
(2x+x) + (14) =20 Combine Like Terms
3x+14=20
- 14 -14 Subtract 14 from both sides
3x = 6
3x/3 6/3 Divide Both Sides by 3
x = 2
Let me know if you still don't understand
45 black dogs because 2/3 of 60 is 45
Given that,
An equation : -9c² +2c +3 = 0
To find,
Find the value of x.
Solution,
We have, -9c² +2c +3 = 0
We can solve it using the formula as follows :

Here, a = -9, b = 2 and c =3
Put the values,

So, the solution are -0.47 and 0.69.
The answer to this, maybe.., is 180