d) [$5^{30}$ +4.$(12-7)^{39}$ ] : $5^{29}$
= [$5^{30}$ +4.$5^{39}$ ] : $5^{29}$
= [$5^{30}$.(4+1) ] : $5^{29}$
=[$5^{30}$.5] : $5^{29}$
= $5^{31}$ : $5^{29}$
=5²
=25
a) x - 12 = 5
x=5+12
x=17
b) 3x + 7 = 2².10
⇒3x + 7 = 4.10=40
⇒3x=40-7
⇒3x=33
⇒x=33:3
⇒x=11
c) 2.(32 - $2^{x+11}$) +10 = 42
⇒2.(32 - $2^{x+11}$) = 42-10=32
⇒32 - $2^{x+1}$= 32:2
⇒32 - $2^{x+1}$=16
⇒$2^{x+1}$=32-16
⇒$2^{x+1}$=16
⇒$2^{x+1}$=$2^{4}$
⇒x+1=4
⇒x=4-1
⇒x=3