Question

Simplify the following:
(3.5a-4.5b)²-(3.5a+4.5b)²

Answer 1

Answer:

-63ab

Step-by-step explanation:

We can use  X²-Y² = (X+Y)(X-Y)

X = 3.5a-4.5b

Y = 3.5a+4.5b

X+Y = 7a

X-Y = -9 b

so (X+Y)(X-Y) = 7a(-9b) = -63ab

or we can open the square

(x-y)² = x²+y²-2xy

(x+y)² = x² + y² + 2xy

x = 3.5a y= 4.5b

(x-y)²- (x+y)² = x²+y²-2xy - (x² + y² + 2xy)

= -4xy

putting x &  y values

= -4(3.5a)(4.5b) = -63 ab

Answer 2

Here is your answer

$(3.5a - 4.5b) {}^{2} - (3.5a + 4.5b) {}^{2} \\ = (3.5a - 4.5b + 3.5a + 4.5b)(3.5a - 4.5b - 3.5a - 4.5b) \\ = (7a)( - 9b) \\ = - 63ab$
Hope it helps you