(x - 7) is.
x2 - 14x = 7 add (14/2)2 to both sidesx2 - 14x 72 = 7 + 72(x - 7)2 = 56 take the square root to both sidesx - 7 = +&- sq. root of 56x = - 7 +&- 2(sq. root of 14)
Notice that the left side of the equation is a perfect square (x - 7)2 = x2 -14x + 49. so (x - 7)2 = 4. Take square root of both sides: x - 7 = ± 2, x = 9, or x = 5.
7x3 + 2x = 607x3 + 2x - 60 = 07x3 - 28 x + 30x - 60 = 07x(x2 - 4) + 30(x - 2) = 07x(x + 2)(x - 2) + 30(x - 2) = 0(x - 2)[7x(x + 2) + 30] = 0(x - 2)(7x2 + 14x + 30) = 0x - 2 = 0 or 7x2 + 14x + 30 = 0x = 2 orx = {-14 +&- square root of [142 - 4(7)(30)]}/(2)(7)x = -14/14 +&- (square root of -644)]/14x = -1 +&- 2i(square root of 161)/14x = -1 +&- (square root of 161)i/7
x2+14x+49 = (x+7)(x+7) when factored
(x - 7) is.
Improved answer:5x2+14x+5 = 5-5x2+14x+5 = 0Solve by completing the square:(x+7)2+5 = 0(x+7)2+5-49 = 0(x+7)2 = 44x+7 = + or - the square root of 44x = -7 + or - the square root of 44
x2 - 14x = 7 add (14/2)2 to both sidesx2 - 14x 72 = 7 + 72(x - 7)2 = 56 take the square root to both sidesx - 7 = +&- sq. root of 56x = - 7 +&- 2(sq. root of 14)
Notice that the left side of the equation is a perfect square (x - 7)2 = x2 -14x + 49. so (x - 7)2 = 4. Take square root of both sides: x - 7 = ± 2, x = 9, or x = 5.
-2 and -3Check:(-2) + (-3) = -5(-2)(-3) = 6Thus -2 and -3 are not the required numbers. let's find them: x + y = -6xy = -5 y = -x -6x(-x - 6) = -5-x^2 - 6x = -5x^2 + 6x = 5x^2 + 6x + 9 = 5 + 9(x + 3)^2 = 14x + 3 = (+ & -)square root of 14x = -3 (+ & -)square root of 14x = -3 + square root of 14 or x = - 3 - square root of 14y = -x - 6y = 3 - square root of 14 - 6 or y = 3 + square root of 14 - 6y = -3 - square root of 14 or y = -3 + square root of 14Check:(-3 + square root of 14) + (-3 - square root of 14) = -6(-3 + square root of 14)(-3 - square root of 14) = -5 ?(-3)^2 - (square root of 14)^2 = -5 ?9 - 14 = -5Check also tow other numbers.
7x3 + 2x = 607x3 + 2x - 60 = 07x3 - 28 x + 30x - 60 = 07x(x2 - 4) + 30(x - 2) = 07x(x + 2)(x - 2) + 30(x - 2) = 0(x - 2)[7x(x + 2) + 30] = 0(x - 2)(7x2 + 14x + 30) = 0x - 2 = 0 or 7x2 + 14x + 30 = 0x = 2 orx = {-14 +&- square root of [142 - 4(7)(30)]}/(2)(7)x = -14/14 +&- (square root of -644)]/14x = -1 +&- 2i(square root of 161)/14x = -1 +&- (square root of 161)i/7
14x = 5 x = 5/14
x2 - 14x + 49 = (x - 7)2
x2+14x+49 = (x+7)(x+7) when factored
6x - 14x = 35 + 11 -8x = 46 8x = -46 8x/8 = -46/8 x = -5.75
Yes because if x2-14x+49 then it is (x-7)(x-7) when factored
Write eqn for weight; x = 14% sol & y = 6% sol which is x + y = 50. Write eqn for solution: .14x + .06y = .12*50 = 6; 2 equations 2 unknowns. Solve: Mult 1st eqn by -.14; now -.14x-.14y = -.14*50 or -7 -.14x-.14y=-7 .14x+.06y=6 0-.08y=-1 or y=12.5 or 12.5mL of 6% solution x+12.5=50 or x=37.5 or 37.5 mL of 14% solution