SOLUTION: what is 18x^2=8? 4x^2=x+3? x^2=8-7x? 8x^2+5x=3+7x? 12^2=-6x? 3x^2-13x=10? 3n^2-2n-5=0? 25p^2=16? please help I'm desperate !!

Algebra ->  Equations -> SOLUTION: what is 18x^2=8? 4x^2=x+3? x^2=8-7x? 8x^2+5x=3+7x? 12^2=-6x? 3x^2-13x=10? 3n^2-2n-5=0? 25p^2=16? please help I'm desperate !!       Log On


   

Question 399099: what is 18x^2=8? 4x^2=x+3? x^2=8-7x? 8x^2+5x=3+7x? 12^2=-6x? 3x^2-13x=10? 3n^2-2n-5=0? 25p^2=16? please help I'm desperate !!
Answer by Tatiana_Stebko(1539) About Me  (Show Source):
You can put this solution on YOUR website!
18x%5E2=8
x%5E2=8%2F18
x%5E2=4%2F9
x=sqrt%284%2F9%29 or x=-sqrt%284%2F9%29
x=2%2F3 or x=-2%2F3
b
4x%5E2=x%2B3
4x%5E2-x-3=0,
FORMULA ax%5E2%2Bbx%2Bc=0
D=b%5E2-4ac
x=%28-b%2Bsqrt%28D%29%29%2F%282%2Aa%29or x+=+%28-b+-+sqrt%28D%29%29%2F%282%2Aa%29+
in your case 4x%5E2-x-3=0, a=4, b=-1, c=-3 put in formula
D=%28-1%29%5E2-4%2A4%2A%28-3%29=49
x+=+%28-%28-1%29+%2B+sqrt%2849%29%29%2F%282%2A4%29=8%2F8=1+or x+=+%28-%28-1%29+-+sqrt%2849%29%29%2F%282%2A4%29=-6%2F8=-3%2F4+
c
x%5E2=8-7x
x%5E2%2B7x-8=0,
a=1, b=7, c=-8 put in formula
D=7%5E2-4%2A1%2A%28-8%29=81
x+=+%28-7+%2B+sqrt%2881%29%29%2F%282%2A1%29=2%2F2=1+ or x+=+%28-7+-+sqrt%2881%29%29%2F%282%2A1%29=-16%2F2=-8+
d
8x%5E2%2B5x=3%2B7x
8x%5E2%2B5x-3-7x=0
8x%5E2-2x-3=0,
a=8, b=-2, c=-3 put in formula
D=%28-2%29%5E2-4%2A8%2A%28-3%29=100
x+=+%28-%28-2%29+%2B+sqrt%28100%29%29%2F%282%2A8%29=12%2F16=3%2F4+ or x+=+%28-%28-2%29+-+sqrt%28100%29%29%2F%282%2A8%29=-8%2F16=-1%2F2+
e
12x%5E2=-6x
12x%5E2%2B6x=0 incomplete quadratic equation
6x%282x%2B1%29=0
6x=0 or 2x%2B1=0
x=0 or x=-1%2F2
f
3x%5E2-13x=10
3x%5E2-13x-10=0,
a=3, b=-13, c=-10 put in formula
D=%28-13%29%5E2-4%2A3%2A%28-10%29=289
x+=+%28-%28-13%29+%2B+sqrt%28289%29%29%2F%282%2A3%29=30%2F6=5+or x+=+%28-%28-13%29+-+sqrt%28289%29%29%2F%282%2A3%29=-4%2F6=-2%2F3+
g
3n%5E2-2n-5=0,
a=3, b=-2, c=-5 put in formula
D=%28-2%29%5E2-4%2A3%2A%28-5%29=64
n+=+%28-%28-2%29+%2B+sqrt%2864%29%29%2F%282%2A3%29=10%2F6=5%2F3+ or n+=+%28-%28-2%29+-+sqrt%2864%29%29%2F%282%2A3%29=-6%2F6=-1+
h
25p%5E2=16
p%5E2=16%2F25
p=sqrt%2816%2F25%29or p=-sqrt%2816%2F25%29
p=4%2F5%29or p=-4%2F5%29
Good luck