Answer:
[tex]x=3[/tex]
Step-by-step explanation:
Let [tex]k(x)=mx+b[/tex] be the expression for the linear function k(x), where m is the slope of the function and this function passes through the point (1,8).
Thus, [tex]m=-4[/tex] and the function expression is
[tex]k(x)=-4x+b[/tex]
If the graph of the function passes through the point (1,8), then its coordinates satisfy the function expression. Substitute them:
[tex]8=-4\cdot 1+b\\ \\8=-4+b\\ \\b=8-(-4)\\ \\b=12[/tex]
Hence,
[tex]k(x)=-4x+12[/tex]
The graph of this function intersects the x-axis at k(x)=0, then
[tex]-4x+12=0\\ \\-4x=-12\\ \\x=3[/tex]
Zero of the function is x=3
