X^2+4x-21=0 Solve for x
Quadractics factorise into double brackets like (x-a)(x-b). We ave to find the facors of -21 which add to make +4. 7 and -3 suffice. (x-3)(x+7) Then x will be equal to 3 and -7 for the equation.
JC
Related Maths GCSE answers
All answers ▸Find the equation of the line L passing through (0, 3) and (5, 7). What would the gradient of a line perpendicular to this line be? What about a line parallel to it?
A ladder 5m long is leaning up against a wall. The foot of the ladder is 3m from the wall. How high up the wall does the ladder reach?
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 find a missing side length in a right-angled triangle?