If f(x)=7-4x, given that f(c)=9, find c
f(c) means let x=c. Remember that c is just an unknown number.
The expression f(c)=9 means that when we put c through the function f(x)=7-4x, it gives the answer 9. Therefore we know 7-4c=9 is true.
Now we have an equation that we can go through in the normal way:
7-4c=9
-4c=2
4c=-2
c=-0.5
EF
Related Maths GCSE answers
All answers ▸A is the point with coordinates (5, 9) B is the point with coordinates (d, 15). The gradient of the line AB is 3. Work out the value of d.
How do I expand (x - 4)(2x + 3y)^2 ?
The point P has coordinates (3, 4) The point Q has coordinates (a, b) A line perpendicular to PQ is given by the equation 3x + 2y = 7 Find an expression for b in terms of a.
How do you solve linear inequalities such as: 5x – 2 > 3x + 11