Answer:
5
Explanation:
Because this is a right triangle, you know that by the Pythagorean theorem:
![√((x+7)^2+x^2)=x+8](https://img.qammunity.org/2021/formulas/mathematics/college/qhi3iz7rqs9elhg3e0xi0pypw8f1l2sl4l.png)
Squaring both sides to get rid of the square root:
![(x+7)^2+x^2=(x+8)^2](https://img.qammunity.org/2021/formulas/mathematics/college/o99h3ze34mbsa3k3m2q6l0lghr68ajqb5a.png)
Expanding all of the parentheses:
![x^2+14x+49+x^2=x^2+16x+64](https://img.qammunity.org/2021/formulas/mathematics/college/f5zai254rbj9quey8894sj6f1dqvpl6t86.png)
Combine like terms:
![x^2-2x-15=0](https://img.qammunity.org/2021/formulas/mathematics/middle-school/7vr8hpk5wylagle36ylf4oqgq02ctwq072.png)
Factor:
![(x-5)(x+3)=0](https://img.qammunity.org/2021/formulas/mathematics/middle-school/6ndeqitvebqdk84dbcv30ifyjihq1xzjew.png)
Since x cannot be negative, it is equal to 5. Hope this helps!