+0

# If 4x=8 (mod20) and 3x=16 (mod 20) then ....;

-1
66
4
+44

deleted

Nov 10, 2019
edited by htzhang919  Nov 16, 2019
edited by Melody  Nov 16, 2019

#1
+2499
+2

I am so sorry I dont have a real strategy for this.

lets guess and check:

 multiply of 20 plus 8 4x = 8 Mod (20) 3x = 16 (mode 20) 28 x = 7 Nope 48 x = 12 x = 12

So 122 = 144

144/20 is

7 with a remainder of 4.

Nov 10, 2019
#2
+44
0

deleted

Nov 10, 2019
edited by htzhang919  Nov 16, 2019
#3
+1816
0

Here’s a copy of the original question.

If $$4x\equiv 8\pmod{20}$$ and $$3x\equiv 16\pmod{20}$$, then what is the remainder when $$x^2$$ is divided by 20?

GA

Nov 16, 2019
#4
+106033
0

Thanks Ginger.

Melody  Nov 16, 2019