Answer:
Option C is correct, i.e. 2x² +7x -4.
Step-by-step explanation:
Given is (2x-1)(x+4)
Applying FOIL method:-
F- multiply First two, O- multiply Outer two, I- multiply Inner two, L- multiply Last two.
So, (2x-1)(x+4) = 2x*x +2x*4 -1*x -1*4
(2x-1)(x+4) = 2x² +8x -1x -4
(2x-1)(x+4) = 2x² +7x -4
Hence, option C is correct, i.e. (2x-1)(x+4) = 2x² +7x -4.
A proportion is a pair of equal ratios.
The number of calculators
= Number of boxes * calculators in each box
=18* 12
= 216 calculators
7(5)-12(5)-5=-45+15
-30 = -30
answer= B. x=5