Question

(a+2)(a-3)-(a+4)(a-7) При a равен - 1/2

Answer 1

Ответ:

21

Объяснение:

(а+2)(а-3) - (а+4)(а-7) = а²-3а+2а-6 - а²+7а-4а+28 = 2а + 22 = 2*(-1/2) + 22 =

= -1 + 22 = 21

Answer 2

Ответ:

-1/2=-0.5

(-0.5+2) (-0.5-3) -(-0.5+4) (-0.5-7)

1) 1.5*(-3.5) =-5.25

2) 3.5*(-7.5) =-26.25

3) -5. 25-(-26.25) =-5.25+26.25=21

ответ:21

Answer 3

To evaluate the expression (a+2)(a-3)-(a+4)(a-7) when a is equal to -1/2, we substitute -1/2 for the variable a and simplify the expression:

(-1/2 + 2)(-1/2 - 3) - (-1/2 + 4)(-1/2 - 7)

Now let's calculate each part separately:

(-1/2 + 2) = 3/2 (-1/2 - 3) = -7/2 (-1/2 + 4) = 7/2 (-1/2 - 7) = -15/2

Substituting these values back into the expression:

(3/2)(-7/2) - (7/2)(-15/2)

Now let's simplify the expression further:

(3/2)(-7/2) = -21/4 (7/2)(-15/2) = -105/4

Substituting these values back into the expression:

-21/4 - (-105/4)

To subtract a negative number, we can change it to addition:

-21/4 + 105/4

Now let's add the fractions:

(-21 + 105)/4 = 84/4 = 21

Therefore, when a is equal to -1/2, the expression (a+2)(a-3)-(a+4)(a-7) evaluates to 21.