Question 408083
1)

{{{x^2-1=0}}}

{{{x^2=1}}}

{{{x}}}=+-{{{sqrt(1)}}}

{{{x1=1}}}

{{{x2=-1}}}


2)

{{{x^2-7=0}}}

{{{x^2=7}}}

{{{x}}}=+-{{{sqrt(7)}}}

{{{x1=2.65}}}

{{{x2=-2.65}}}


3)

{{{3x^2-12=0}}}

{{{x^2=12}}}

{{{x}}}=+-{{{sqrt(12)}}}

{{{x1=3.46}}}

{{{x2=-3.46}}}


4)

{{{5x^2-15=0}}}


{{{5x^2=15}}}


{{{5x^2/5=15/5}}}


{{{x^2=3}}}

{{{x}}}=+-{{{sqrt(3)}}}

{{{x1=1.73}}}

{{{x2=-1.73}}}



I will add here your questions from 16-25....


16.
16)x^2+2x-3=0.


*[invoke quadratic_formula 1, 2, -3, "x"]


17)x^2-5x+6=0

*[invoke quadratic_formula 1, -5, 6, "x"]


18)x^2-7x-8=0

*[invoke quadratic_formula 1, -7, -8, "x"]


19)x^2+x-20=0

*[invoke quadratic_formula 1, 1, -20, "x"]

20)6-x-x^2=0..reorder 
-x^2 -x +6 =0

*[invoke quadratic_formula -1, -1, 6, "x"]


21)4+5x+x^2=0
x^2+5x+4=0

*[invoke quadratic_formula 1, 5, 4, "x"]


22)24+2x-x^2=0
-x^2 +2x + 24=0

*[invoke quadratic_formula -1, 2, 24, "x"]


23)8x^2-1=0

*[invoke quadratic_formula 8, 0, -1, "x"]


24)6x^2+5x+1=0


*[invoke quadratic_formula 6, 5, 1, "x"]


25)3x^2-5x-28=0 

*[invoke quadratic_formula 3, -5, -28, "x"]