Given f(x)= 8 − x^2, solve f(3x) = -28
First substitute (3x) into the equation for f(x), giving f(3x) = 8 - 9x2. This is then equal to -28 and so it is remains to solve the equation 8 - 9x2 = -28. This can be written as 9x2 = 36, dividing through by 9 gives x2 = 4 and so x = ±2.
GG
Answered by George G. • Further Mathematics tutor
4438 Views
See similar Further Mathematics GCSE tutorsRelated Further Mathematics GCSE answers
All answers ▸Find the stationary points of y=x^3 + 3x^2 - 9x - 4
The coefficient of the x^3 term in the expansion of (3x + a)^4 is 216. Find the value of a.
How do I know I can multiply two matrices and if so, how do I do it?
x^3 + 2x^2 - 9x - 18 = (x^2 - a^2)(x + b) where a,b are integers. Work out the three linear factors of x^3 + 2x^2 - 9x - 18. (Note: x^3 indicates x cubed and x^2 indicates x squared).