Given:
The distance between the two points (11, 1) and (x, 17) is 20.
To find:
The possible values of x.
Solution:
Distance formula is:
![D=√((x_2-x_1)^2+(y_2-y_1)^2)](https://img.qammunity.org/2021/formulas/mathematics/college/c00i76k277fqbp0j3yzz4iqutiurlwhml8.png)
Using this formula, the distance between (11, 1) and (x, 17) is
![D=√((x-11)^2+(17-1)^2)](https://img.qammunity.org/2021/formulas/mathematics/high-school/riu1jjis7p9pefcnne7r9k7c3qlq1q70qh.png)
![20=√(x^2-22x+121+(16)^2)](https://img.qammunity.org/2021/formulas/mathematics/high-school/uc33pzb2w780awkqch8ykzhdul7n0wz8bc.png)
![20=√(x^2-22x+121+256)](https://img.qammunity.org/2021/formulas/mathematics/high-school/7gdi75czqu0nd6nag3u7bgj8rd1d0agjr3.png)
Taking square on both sides.
![400=x^2-22x+377](https://img.qammunity.org/2021/formulas/mathematics/high-school/rplnp1setrpyzundvpz89d92bsqag9uzqd.png)
![0=x^2-22x+377-400](https://img.qammunity.org/2021/formulas/mathematics/high-school/6xihyel8pf5mp2w1wau9oy1dwo5lm2kyhk.png)
![x^2-22x-23=0](https://img.qammunity.org/2021/formulas/mathematics/high-school/g1di8yssiykzq2awf0sl1gny4leo3g1pke.png)
Splitting the middle term, we get
![x^2-23x+x-23=0](https://img.qammunity.org/2021/formulas/mathematics/high-school/sic5u8f1esrdbne0yo8fcgr4n4mi4x4wqj.png)
![x(x-23)+(x-23)=0](https://img.qammunity.org/2021/formulas/mathematics/high-school/lw5twsiqt41jeb74hqml0qz82axal38tpi.png)
![(x-23)(x+1)=0](https://img.qammunity.org/2021/formulas/mathematics/high-school/y0zcfv1o7lsva32mlh0qw5a86pkdbhbycu.png)
Using zero product property, we get
![x=-1,23](https://img.qammunity.org/2021/formulas/mathematics/high-school/sm40unhh1iw9n8z6p65r0ux814ie5ja5cs.png)
Therefore, the possible values of x are -1 and 23.