5 + 5 + 5 - 5 + 5 + 5 - 5 + (5 x 0) = 15
x2 + 10x = 0 x2 + 10x + 25 = 25 (x + 5)2 = 25 x + 5 = +-5 x1 = 0 x2 =10
4, -5
x2 - 10x + 25 = 0(x - 5)(x - 5) = 0x - 5 = 0x = 5
55.505 = (5 x 10) + (5 x 1) . (5/10) + (0/100) + (5/1000)
solving for the x variable given that x2-6x+5=0 factoring the polynomial gives (x-1)(x-5)=0 which leaves you with your two answers, x=1, 5 or you could have used the quadratic equation x = [ -(-6) plus/minus sqrt( (-6)2 - 4*1*5 ) ] / (2*1) x = [ 6 plus/minus sqrt( 36-20 ) ] / 2 x = [ 6 plus/minus 4 ] / 2 x = 3 plus/minus 2 x = 5, 1
(5+5) + (5-5) + (5 + 5 - 5) + (5 x 0) = 10 + 0 + 5 + 0 = 15
x+4x+5 = 0 5x + 5 = 0 5x = -5 x = -1
x = -1/2 or -5 2x2 + 11x + 5 = 0 ⇒ (2x + 1)(x + 5) = 0 ⇒ (2x + 1) = 0 → x = -1/2 or (x + 5) = 0 → x = -5
(x+4)(x+5) = 0 x = -4 v x= -5 However this can also be an answer: (x+4)(x+5) = 0 x2 + 9x + 20 = 0
X should be zeroas:X + 5 = 2X + 5so, 2X - X = 0 or X = 0
x2 + 9x + 20 = 0 ∴(x + 4)(x + 5) = 0 ∴x ∈ {-5, -4}
-5
x=0
X = 5
x2 + 14x + 45 = 0 => x2 + 9x + 5x + 45 = 0 => x(x + 9) + 5(x + 9) = 0 (x + 9)(x + 5) = 0 so that x = -5 or x = -9
0
x2+6x+5=0(x+1)(x+5)=0x=-1 and x=-51-6+5=0 and 25-30+5=0 so both answers work.