factor 7x^4+51x^2+14
Let's factor in ℝ: 7x4 + 51x2 + 14
Let's define: X = x2
You can transform this expression into: 7X2 + 51X + 14
Given the quadratic form aX2 + bX + c, let's compute the discriminant: Δ = b2 -4ac. Here a = 7, b = 51 and c = 14
Δ = 512 -4·7·14
ⓘ Powers are computed before multiplications, additions and subtractions. An integer power is a repeated product: 512 = 51·51 = 2601■Multiplications are done before additions and subtractions: 4·7 = 28
Δ = 2601 -28·14
ⓘ Multiplications are done before additions and subtractions: 28·14 = 28·(10 + 4) = 28·10 + 28·4 = 280 + 112 = 392
Δ = 2601 -392
ⓘ Start from 2601 and move back 392 on the number line: 2601 -392 = 2209
Δ = 2209
Since Δ > 0, the equation has two roots:
The quadratic formula gives X1 = -b -Δ2a = -51 -22092·7
X1 = -51 -22092·7
ⓘ The square root of a number is the positive number whose square is that number: 2209 = 47; 472 = 2209
ⅰ 2·7 = 14
X1 = -51 -4714
ⓘ The numerator and the denominator are computed before the division: -51 -47 = -98
X1 = -9814
We divide the numerator and denominator of 9814 by the common factor: 14, which gives the new expression: 7
X1 = -7
The quadratic formula gives X2 = -b + Δ2a = -51 + 22092·7
X2 = -51 + 22092·7
ⓘ The square root of a number is the positive number whose square is that number: 2209 = 47; 472 = 2209
ⅰ 2·7 = 14
X2 = -51 + 4714
ⓘ The numerator and the denominator are computed before the division: -51 + 47 = -4
X2 = -414
ⓘ We simplify the fraction by dividing the numerator and the denominator by 2, their greatest common divisor: -414 = -2·27·2 = -27
X2 = -27
A trinomial with roots X1 and X2 is a·(X -X1)·(X -X2); bringing the coefficient into the brackets: 7·(X + 7)·(X + 27) = (X + 7)·(7X + 2)
Factors found: (X + 7)·(7X + 2)
ⓘ A square being never negative, x2 + 7 is never zero and cannot be factored in ℝ
▶Factored expression:   (x2 + 7)·(7x2 + 2)