The values of x such that the functions have the specified values are;
11. x = -9
12. x = 8
13. x = -2
14. x = 4.5
15. x = -2
16. x = 15
What is a function; A function is a rule, definition or law that maps the elements of one set to the elements of a second set, such that each element in the first set maps to only one element in the second set.
11. h(x) = -7·x, h(x) = 63
Therefore, we get;
63 = -7·x
x = 63/(-7)
x = -9
12. r(x) = 3·x, r(x) = 24
Therefore, 24 = 3·x
x = 24/3
x = 8
13. m(x) = 4·x + 15; m(x) = 7
Therefore, 7 = 4·x + 15
4·x = 7 - 15
4·x = -8
x = -8/4
x = -2
14. k(x) = 6·x - 12
k(x) = 15
Therefore, 15 = 6·x - 12
6·x - 12 = 15
6·x = 15 + 12
6·x = 27
x = 27/6
x = 9/2
15. q(x) = 0.5·x - 3; q(x) = -4
-4 = 0.5·x - 3
0.5·x - 3 = -4
0.5·x = -4 + 3
0.5·x = -1
x = -1/0.5
x = -2
16. j(x) = (-4/5)·x + 7; j(x) = -5
(-4/5)·x + 7 = -5
(-4/5)·x = -5 - 7
x = -12
x = (-5/4) × (-12)
x = 15