Answer:
![\displaystyle [-2, 7]](https://tex.z-dn.net/?f=%5Cdisplaystyle%20%5B-2%2C%207%5D)
Step-by-step explanation:
You want to eradicate one pair of variables so they are set to zero. It does not matter which pair is selected:

{½[4x + 2y = 6]
{−2x + 2y = 18
>> 
Plug this back into the system to get the x-value of 
I am joyous to assist you at any time.
B.) Organ systems must work together to keep the body functioning
-.25a-4=4
Add for on both sides
-.25a=8
Divide by -.25
A=
Answer:
By comparing the ratios of sides in similar triangles ΔABC and ΔADB,we can say that 
Step-by-step explanation:
Given that ∠ABC=∠ADC, AD=p and DC=q.
Let us take compare Δ ABC and Δ ADB in the attached file , ∠A is common in both triangles
and given ∠ABC=∠ADB=90°
Hence using AA postulate, ΔABC ≈ ΔADB.
Now we will equate respective side ratios in both triangles.

Since we don't know BD , BC let us take first equality and plugin the variables given in respective sides.

Cross multiply

Hence proved.
Too hard for me. I'm only in 5th grade