How do you set up the quadratic formula with the correct numbers? x² - 4x - 15 = 0
2 Answers
Explanation:
Recall;
Comparing you will have;
Using Quadratic Formula;
Plugging the values into the equation..
Explanation:
#"the solution of a quadratic equation in "color(blue)"standard form"#
#•color(white)(x)ax^2+bx+c=0;a!=0#
#"can be solved using the "color(blue)"quadratic formula"#
#•color(white)(x)x=(-b+-sqrt(b^2-4ac))/(2a)#
#x^2-4x-15=0" is in standard form"#
#"with "a=1,b=-4" and "c=-15#
#x=(-(-4)+-sqrt((-4)^2-(4xx1xx-15)))/(2xx1)#
#color(white)(x)=(4+-sqrt(16+60))/2#
#color(white)(x)=(4+-sqrt76)/2=(4+-2sqrt19)/2=2+-sqrt19#
#x~~-2.36" or "x~~6.36" to 2 dec. places"#