Question

Pe 4 si pe 5 va rog!
Dau coroana + multumesc + 20 puncte
Spor!:)

Answer 1

4. (x+3)²-25=

=(x+3+5)(x+3-5)=(x+8)(x-2)

(x-4)(3x+7)-(x-4)(4x+2)+3(x+4)=

=3x²+7x-12x-28-(4x²+2x-16x-8)+3x+12=

=3x²+7x-12x-28-(4x²-14x-8)+3x+12=

=3x²+7x-12x-28-4x²+14x+8+3x+12= -x²+14x-8

5. a) BD=AB√2

BD=8√2cm

b) ΔDAM(m(∡A)=90°)⇒AD²+AM²=DM²⇒DM²=8²+6²⇒DM²=64+36⇒

⇒ DM²=100⇒DM=10cm

c) A ABCD=AB²

A ABCD=8²

A ABCD=64cm²

AΔDAM=AD×AM/2

AΔDAM=8×6/2

AΔDAM=4×6

AΔDAM=24cm²

AΔBCD=BC×CD/2

AΔBCD=8×8/2

AΔBCD=4×8

AΔBCD=32cm²

AΔBMD= A ABCD-AΔDAM-AΔBCD

AΔBMD=64cm²-24cm²-32cm²

AΔBMD=8cm²