Answer:
and.. thanks
Step-by-step explanation:
You can just substitute the m in the first equation
like this ; 2(10 - 2n) - 7n = -18.5
20. 64. 2.7
+29 +49 58.6
------ ------ ---------
49. 113 60 .3
49+60.3+113=21.5
If it has a single zero that means it has to be just touching the x-axis with its tip.
We know that if it has only one zero, the discriminant equals 0.
So,

Solving for k,
.
Hope this helps.