Answer:
√308 or 17.5
Step-by-step explanation:
c^2=a^2+b^2
c^2-a^2=b^2
Substitute
18^2-4^2=b^2
324-16=b^2
b^2=308
b=√308 or b=17.5
j+8k
first -2i+j+4k-3i-2j+7k+5i+2j-3k
Yes
Yes, because each x has one specific y.