Question

Solve by using identities:
a) (69)² b) 86x94 c)(3a+5)² d) (7a-6)​

Answer 1

Step-by-step explanation:

(60+9) square

(a+b) square= a2 +2ab +b2

60*60+2*60*9+9*9

3600+1080+81

4761

(90+4)*(90-4)

(a+b) (a-b) = a2-b2

90*90-4*4

8100-16

8084

(a+b) square= a2+2ab+b2

3a*3a +2*3a*5+5*5

9a2+30a+25