Two stocks are believed to satisfy the two$-$factor model

$r_1={}_1+2f_1+f_2$

$r_2={}_2+3f_1+4f_2$

In addition, there is a risk$-$free asset with a rate of return of $10\%.$ It is known that $\frac{?}{\text{b}\text{a}\text{r}}(r_1)=15\%$ and $\frac{?}{\text{b}\text{a}\text{r}}(r_2)=20\%.$ What are the values of ${}_0,{}_1$ and ${}_2$ for this model?