x2 + 2x - 13 = 2 x2 + 2x - 15 = 0 (x + 5)(x - 3) = 0 x + 5 = 0 and x - 3 = 0 so x = -5 and x = 3
x2 + 2x - 15 = 0(x + 5) (x - 3) = 0x = -5x = +3
3x2 + 2x + 2 = 0 Can not be factored. You can however solve it for x: 3x2 + 2x = -2 x2 + 2x/3 = -2/3 x2 + 2x/3 + 1/9 = -2/3 + 1/9 (x + 1/9)2 = -5/9 x + 1/9 = ±√(-5/9) x = -1/9 ± i√(5/9) x = -1/9 ± i√5 / 3 x = -1/9 ± 3i√5 / 9 x = (-1 ± 3i√5) / 9
2x2-5 = 0 +5 +5 2x2 = 5 /2 /2 x2 = 5/2 sqrt(x2) = sqrt (5/2) x = sqrt(5/2) Ps: Sqrt means square root
x2=9x-20 x2-9x+20=0 Factor: (x-4)(x-5)=0 x={4,5}
x2 + 2x - 13 = 2 x2 + 2x - 15 = 0 (x + 5)(x - 3) = 0 x + 5 = 0 and x - 3 = 0 so x = -5 and x = 3
x2-2x-10-5 = 0 x2-2x-15 = 0 (x+3)(x-5) = 0 x = -3 or x = 5
x2 - 2x - 10 = 5 x2 - 2x - 15 = 0 (x - 5)(x + 3) = 0 x - 5 = 0 and x + 3 = 0 So, x = 5 and x = -3
x2+8x = -3x2+5 4x2+8x-5 = 0 (2x+5)(2x-1) = 0 x = -5/2 or x = 1/2
x2 + 2x - 15 = 0(x + 5) (x - 3) = 0x = -5x = +3
x2 + 2x - 15 = (x - 3)(x + 5)
x2-2x-15 = (x+3)(x-5) when factored
x2 - 2x + 55 = 90x2 - 2x - 35 = 0(x+5)(x-7) = 0x = -5, 7
No real roots
x2-2x = 15 x2-2x-15 = 0 (x-5)(x+3) = 0 Therefore: x = 5 or x = -3
x2 - 2x - 15 = 0
If x2 + 5 = -2x, then x2 + 2x + 5 = 0 This equation cannot be readily factored so using the quadratic formula :- x= {-2 ± √[(-2)2 - 4x5]} ÷ 2 = {-2 ±√-16} ÷ 2 = -1 ± 2i Therefore x = -1 + 2i or x = -1 - 2i