Question

I will mark you brainliest of you answer this question correctly with steps​

Answer 1

Step-by-step explanation:

1.

(7x³ + 8x² - 3)(x² - 5) ; x = 5

Substituting x = 5 in the given expression, we get

[7(5)³+8(5)²-3] [(5)²-5]

= [7(125)+8(25)-3] [25-5]

= (875+200-3) (20)

= (1072)(20)

= 21440

2.

$(\frac{ - 3}{5} {x}^{2} + xy - \frac{2}{7} {y}^{2} )( \frac{ - 3}{8} x + \frac{1}{3} y)$

x = 2, y = -1

Substituting the values in given expression, we get

Term 1:

$( \frac{ - 3}{5} ( {2})^{2} + (2)( - 1) - \frac{2}{7} ( { - 1})^{2} )$

$= ( \frac{ - 3}{5} (4) - 2 - \frac{2}{7} )$

$= \frac{ - 12}{5} - \frac{16}{7}$

$= \frac{ - 84 - 80}{35}$

$= \frac{ - 164}{35}$

Term 2:

$\frac{ - 3}{8} (2) + \frac{1}{3} ( - 1)$

$= \frac{ - 3}{4} - \frac{1}{3}$

$= \frac{ - 9 - 4}{12}$

$= \frac{ - 13}{12}$

Final expression:

$\frac{ - 164}{35} \times \frac{ - 13}{12}$

$= \frac{ - 41}{35} \times \frac{ - 13}{3}$

$= \frac{533}{105}$

Hope this helps!