Question

question 15 (1) please solve it

Answer 1

4a² - b² + 6a² -7b²
= 10a² - 8 b²
= 10 x (-1)² - 8 x (-3)²
= 10 - 8 x 9
= 10 - 72
= - 62

Answer 2

given is :
x=2
a=-1
B=-3
simplifying part I)
$i)4 {a}^{2} - {b}^{2} + 6{a}^{2} - 7 {b}^{2}$
simplifying first :
10a^2 -8b^2

now putting
x=2
a=-1
B=-3

(10*-1*-1) - (8*-3*-3)
10-72
<<=62>> Answer ...

part ii)
$3 {x}^{2} - 8ab + 4 {x}^{2} + 11ab$
simplifying first
7x^2 +3ab

now putting
x=2
a=-1
B=-3
(7*-1*-1) +(3*-1*-3)
7+9
<<=16>>

$hope \: it \: helps$