The sentence "15% of 4x is 20 less than x"
translates to 0.15 • (4x) = x – 20
Solving that…
0.15(4x) = x - 20 multiplipy 0.15•4
0.6x = x - 20 subtract x from both sides
-0.4x = - 20 divide both sides by -0.4
x = 50
Answer:
(1/4,-121/8)
Step-by-step explanation:
Answer:
(x+1)(x-1)(x+3)(x-3)
Step-by-step explanation:
x4-10x^2+9
Group expression so that the coefficients of the x^2 terms add up to +9.
= x^4 -9x^2 - x^2+9
match coefficients in both groups
= x^4 -9x^2 - (x^2-9)
factor each group
= x^2 (x^2-9) - 1(x^2-9)
now factor out the common factor (x^2-9)
= (x^2-1)(x^2-9)
Finally, factor each quadratic factor
= (x+1)(x-1)(x+3)(x-3)
