Question

(3p-2a)(3p+2a)-3p(3p+5),если p=2/3,a=-2

Answer 1

9p²-4a²-9p²-15p= -4a²-15p= -4*4-15*2/3= -16-10= -26

Answer 2

Заметим формулу:(а-б)(а+б)=а2-б2

9р2-4а2-9р2-15р=-4а2-15р /при р*2/3, а=-2,

-4*(-2)2-15*2/3= -4+4-10=-10

Answer 3

To evaluate the expression (3p-2a)(3p+2a)-3p(3p+5) with the given values p = 2/3 and a = -2, we substitute the values and simplify the expression step by step.

Let's start with the expression:

(3p-2a)(3p+2a) - 3p(3p+5)

Substituting p = 2/3 and a = -2:

(3(2/3) - 2(-2))(3(2/3) + 2(-2)) - 3(2/3)(3(2/3) + 5)

Simplifying further:

(2 - (-4/3))(2 + (-4)) - 3(2/3)(2/3 + 5)

(2 + 4/3)(2 - 4) - 3(2/3)(17/9)

(6/3 + 4/3)(-2) - (2/1)(17/9)

(10/3)(-2) - (34/9)

-20/3 - 34/9

To subtract these fractions, we need a common denominator, which is 9 * 3 = 27:

(-20/3)(9/9) - (34/9)(3/3)

-180/27 - 102/27

Combining the fractions:

(-180 - 102)/27

-282/27

Simplifying the fraction:

-10(6/27)

-10/27

Therefore, when p = 2/3 and a = -2, the expression (3p-2a)(3p+2a)-3p(3p+5) evaluates to -10/27.