Answer:
[tex]k=14[/tex]
Step-by-step explanation:
Given:
[tex]x^{2}+kx+49 = 0[/tex]
[tex]x = -7[/tex]
Substitution can be used to find the value of [tex]k[/tex]:
[tex](-7)^{2}+(-7)k+49 = 0[/tex]
[tex]49-7k+49 = 0[/tex]
[tex]98 -7k = 0[/tex]
[tex]k = 14[/tex]
Hope this helps :)