Answer:
(3w - 7)(3w + 7)
Step-by-step explanation:
The expression is a difference of squares and factors in general as
a² - b² = (a - b)(a + b)
Thus
9w² - 49
= (3w)² - 7²
= (3w - 7)(3w + 7)
She would get £2.50
4 times 2 is 8
2 times 3 is 6
0.7 times 5 is 3.5
Add them together
Minus it from 20
It equals £2.50
C = 8.5x + 6y
Rearrange the equation by making the side with x, be on the Left Hand Side (LHS)
8.5x + 6y = C
Subtract 6y from both sides of the equation
8.5x + 6y - 6y = C - 6y
8.5x = C - 6y
Divide both sides of the equation by 8.5
(8.5x/8.5) = (C - 6y)/8.5
x = (C - 6y)/8.5
I hope this helped.