Solve 5x^2 = 10x + 4 Give your answers to 2 decimal places. [4 marks]
5x^2 = 10x + 4 5x^2 - 10x = 4 5x^2 - 10x - 4 = 0 ax^2 +bx +c = 0 x = (-b (+/-) ( b2 -4ac)1/2) /(2a) x = (--10 (+/-) ((-10)2- (4 x 5 x -4))1/2)/(2 x 5) x = (10 (+/-) (100 + 80)1/2)/10 x = (10 (+/-) (180)1/2 )/10 x = 2.341(...) and –0.341(...) x= 2.34 and –0.34 (to 2.d.p)
JT
