Hello,
the first step should be to distribue:
-4(3-5x)= -12+20x
Teh resolution may be:
-4(3-5x)>=-6x+9
==>-12+20x>=-6x+9
==>20x+6x>=9+12
==>26x>21
==>x>=21/26
But an other way may be used:
-4(3-5x)>=-6x+9
==>3-5x<= -6x/(-4)+9/(-4)
==>-5x-3/2 x<=-9/4 -3
==>-13/2 x <=-21/4
==>x>= -21/4 *(-2/13)
==>x>=21/(2*13)
==>x>=21/26
Answer: N=800/5
N=160
He needs to save $160 every week to get $800 in 5 weeks
hope this helps.
1. AB 3-2/-1-1
-1/2
BC 2+1/1+3
3/4
AC 3+1/-1+3
4/2=2
It is a right triangle
2. JK -1-2/4+3
-3/7
LM -2+5/-5-2
-3/7
KL -1+5/4-2
<u>4/2=2</u>
JM 2+2/-3+5
<u>4/2=2
</u><u />The quadrilateral is a parallelogram
