Question

(4-3а)^2-а(7а-24) , при а = -3/4

Answer 1

$\frac{137}{8} = 17\frac{1}{8} = 17.125$.

Answer 2

To evaluate the expression (4-3a)^2 - a(7a-24) with a = -3/4, we substitute the value of a into the expression and simplify:

(4 - 3(-3/4))^2 - (-3/4)(7(-3/4) - 24)

First, let's simplify the terms inside the parentheses:

(4 + 9/4)^2 - (-3/4)(49/4 - 24)

Next, we'll simplify the fraction inside the parentheses:

(4 + 9/4)^2 - (-3/4)(49/4 - 96/4)

Now, let's calculate the values inside the parentheses:

(4 + 9/4)^2 - (-3/4)(-47/4)

Next, let's simplify the fraction multiplication:

(4 + 9/4)^2 - (3/4)(47/4)

Now, let's calculate the values inside the parentheses:

(16/4 + 9/4)^2 - (3/4)(47/4)

Now, let's simplify the fraction addition:

(25/4)^2 - (3/4)(47/4)

Next, let's calculate the values inside the parentheses:

(625/16) - (3/4)(47/4)

Now, let's simplify the fraction multiplication:

625/16 - (3 * 47)/(4 * 4)

Now, let's calculate the values inside the parentheses:

625/16 - 141/16

Finally, subtracting the fractions:

(625 - 141)/16

Simplifying the subtraction:

484/16

And simplifying the fraction:

121/4

Therefore, when a = -3/4, the expression (4-3a)^2 - a(7a-24) evaluates to 121/4.