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
4174 Views
See similar Further Mathematics GCSE tutorsRelated Further Mathematics GCSE answers
All answers ▸The circle c has equation x^2+ y ^2=1 . The line l has gradient 3 and intercepts the y axis at the point (0, 1). c and l intersect at two points. Find the co-ordinates of these points.
Why does tanx = sinx/cosx ?
A straight line passes trough the points A(-4;7); B(6;-5); C(8;t). Use an algebraic method to work out the value of t.
If z=4+i, what is 1/z? (in the form a+bi)