Hi guys i'm trying to understand this problem and i've tried multiple attempts to solve it but don't uderstand the fundamentals of what is happening here.
$$
\frac57(y+3)=20
$$
At first I started by trying to -3 from both sides but this didn't produce the answer so then I tried multiplying both sides by 7 but don't understand why we wouldnt multiply the brackets by 7?
Any help would be greatly appreciated.
Best Answer
Just like unpacking a crate, the last in is the first out. Someone took $y$ and added $3$. THEN they multiplied by $5/7.$ So when you're unpacking, you first deal with the $5/7$. Multiply by $7/5$ to get
$$\frac{7}{5}\cdot \frac{5}{7}(y+3) = \frac{7}{5}\cdot 20$$
$$y+3 = 28.$$
Now that you cleared out the $5/7$, the path is clear for unpacking the $3$. Subtract $3$ from both sides
$$y = 25.$$