Answer:
81
Step-by-step explanation:
(9x - 4)(9x + 4) = ax² - b
81x² - 36x + 36x - 16
= 81x² - 16
=> a = 81
Answer:
all work is answer and shown and pictured
Answer:
Length 37 cm, width 25 cm.
Step-by-step explanation:
Let the original dimensions be length x and width x - 12 cms.
The new dimensions will be length (x - 2) and width (x - 12 - 2) = x-14 cm.
So , from the areas, we have:
x(x - 12) - (x - 2)(x - 14) = 120
x^2 - 12x - (x^2 - 16x + 28) = 120
-12x + 16x - 28 = 120
4x = 148
x = 37 cms
So the length was 37 cm and the width was 37-12 = 25 cm.
Try, pls, this solution (see the attachment).
Answer:
option 2
Step-by-step explanation:
Substitute x = - 5 into f(x) , that is
f(- 5) = 4(- 5) - 7 = - 20 - 7 = - 27
