If ∣x∣=8, ∣y∣=13 and ∣x+y∣=15, determine ∣x-y∣. You may want to draw a diagram to help with your solution.

Answer 1

say x = 8 i + 0 j
y = a i + b j
x+y = (a+8) i + b j
so
a^2+b^2 = 169
(a+8)^2 + b ^2 = 225

a^2 + 16 a + 64 + 169 -a^2 = 225
etc

Answer 2

i don't understand