Hello,
<span>We have that:
(4x+10)+(2x-1)=9x-15
</span>We solve the equation:
4x+10+2x-1=9x-15;
6x+9=9x-15;
6x-9x=-15-9;
-3x=-24;
3x=24;
<span>from which
</span>x=24:3=8
<span>Then:
DF=9x-15=(9</span>×8)-15=72-15=57
bye :-)
The answer is the first choice - see picture for solution:
the answer is
30 x 5 + 9 x 5