Answer:
see explanation
Step-by-step explanation:
Let u = x² ( choice of variable is flexible ), then
4u² - 21u + 20 = 0 ← expressed as a quadratic
This can now be solved for u and converted back into terms of x
7(3 + 9) = 7(3) + 7(9) = 21 + 63
Answer:
(x + 7)^2 = 64
Step-by-step explanation:
x^2 + 23x – 19 = 9x - 4
x^2 + 23x - 9x = -4 + 19
x^2 + 14x = 15 = 0
Completing the square:
(x + 14/2)^2 - (14/2)^2 = 15
(x + 7)^2 - 49 = 15
(x + 7)^2 = 64
