Answers

2015-07-25T11:58:54+08:00
The number is 2

2×3 + 2^2
=6+4
=10
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2015-07-26T14:05:00+08:00
X²+3x=10
x²+3x-10=0
given:
a=1
b=3
c=-10

solution:
x=-b±√b²-4ac/2a
x=-3±√9-4(1)(-10)/2
x=-3±√9+40/2
x=-3±√49/2
x=-3±7/2
x1=-3+7/2
x1=4/2
x1=2 (answer)
x2=-3-7/2
x2=-10/2
x2=-5 (answer)

checking:
x=2
x²+3x=10
(2)²+3(2)=10
4+6=10
10=10
x=-5
x²+3x=10
(-5)²+3(-5)=10
25-15=10
10=10
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