By the Pythagorean Theorem:
L^2=20^2+15^2
L^2=400+225
L^2=625
L=25 m
Do you mean add are subtract
i will glad to help in comments
if you awnser
Answer:
-6<w<8
Step-by-step explanation:
-6<w<8
= 
The 2 right triangles are similar and so the ratios of corresponding sides are equal
The corresponding sides are x and 2, 6 and 1.5, hence
= 