Question

The roots of the quadratic equation x²-4x-8=0 are 5.464,-1.464. The roots correct to 3 significant figures are
5.46 and -1.46
5.464 and -1.464
5.47 and -1.47
5.460 and -1.460​

Answer 1

Answer:

x^2-2.x.2+2^2-2^2-8=0

(x-2)^2-12=0

(x-2)^2=(√12)^2

x-2=√12 and -√12

x=2+√12 and 2-√12

√12=3.464

So x=5.464 and -1.464