Answer:
-7
Step-by-step explanation:
The coordinates of the point wich divide the segment AB, where [tex]A(x_A,y_A),\ B(x_B,y_B)[/tex] in ratio [tex]m:n[/tex] can be calculated using formula
[tex]C\left(\dfrac{nx_A+mx_B}{m+n},\dfrac{ny_A+my_B}{m+n}\right)[/tex]
In your case,
[tex]A(-4,-10)\\ \\B(-11,-7)\\ \\m:n=3:4\Rightarrow m=3,\ n=4[/tex]
Hence,
[tex]C\left(\dfrac{4\cdot (-4)+3\cdot (-11)}{3+4},\dfrac{4\cdot (-10)+3\cdot (-7)}{3+4}\right)\\ \\C\left(-\dfrac{49}{7},-\dfrac{61}{7}\right)\\ \\C\left(-7,-\dfrac{61}{7}\right)[/tex]
Therefore, x-coordinate of the point that divides AB into a 3:4 ratio is -7.