Question

use the quadratic formula to find the zeros of the function round to the tense of necessary y= 17x^2-21

Answer 1

`y=17x^2-21\\\\\text{The zeros of the function:}\ y=0\iff17x^2-21=0\ \ \ |+21\\\\17x^2=21\ \ \ |:17\\\\x^2=(21)/(17)\to x=\pm\sqrt{\dfrax{21}{17}}\\\\x\approx-1.1\ \vee\ x\approx1.1`


`\text{Use the quadratic formula:}\\\\y=17x^2-21\\\\a=17;\ b=0;\ c=-21\\\\b^2-4ac=0^2-4\cdot17\cdot(-21)=1428\\\\x_1=(-b-√(b^2-4ac))/(2a);\ x_2=(-b+√(b^2-4ac))/(2a)\\\\x_1=(-0-√(1428))/(2\cdot17)=-(√(1428))/(34)\approx-1.1\\\\x_2=(-0+√(1428))/(2\cdot17)=(√(1428))/(34)\approx1.1`