Question

Expand (7x + 5)^2 by using identity.​

Answer 1

Question:-

${(7x + 5)}^{2} = \: ?$

Using Formula:-

${(a + b)}^{2} = {a}^{2} + 2ab + {b}^{2}$

Solution:-

${(7x + 5)}^{2} \\ {(7x)}^{2} + 2 \times 7x \times 5 + {(5)}^{2} \\ 49 {x}^{2} + 70x + 25$

u'r done!!

Thnx✌️♥️~

Answer 2

Step-by-step explanation:

Let a=7x and b=5

According to identity:

identity:(a+b)^2=a^2+2ab+b^2

(7x+5)^2=(7x)^2+2*7x*5+(5)^2

49x^2+70x+25

Solving by formula method:

D=b^2-4ac

=(70)^2-4*49*25

=4900-4900

=0

Hence it has real and equal roots.

By formula method

x=-b+-√D/2a

=-70+-√0/98

=-70+-/98

x = -10/14 OR

x =-10/14

Hope it helps