Question

The function f is defined by f(x)=a−2x, where a is a constant. Find a, if the graph of f passes through the point (8,−21).

Answer 1

-21 = a - 2(8) because the graph passes through (8,
-21)

a = -21 + 16 = -5 answer

Answer 2

value of constant a is (-5).

Explanation:

The function f is defined by f(x) = a - 2x

where a is a constant.

We have to find the value of a if the graph passes through (8, - 21)

If function passes through ( 8, -21 ) then x and y value of this point will satisfy the equation.

y = f(x) = a -2x

-21 = a -2(8)

-21 = a - 16

a = -21 + 16

= -5

Therefore, value of constant a is (-5).