"The sum of the number 'n' and 31" . . . . . (n + 31)
"17 times the sum" . . . . . 17(n + 31)
The equation . . . . . 17(n + 31) = 357
If 5 is a factor of the number, then its ones place is either a 5 or a zero.
2+4z-18
change it so it's an equation
2+4z-18=0
then get 4z alone on one side by subtracting 4z from both sides
2-18=-4z
-16= -4z
divide both sides by -4
a negative divided by a negative becomes positive
4 =z
plug it in
2+4(4)-18
4x4 is 16
2+16-18=0
0=0
the same can be done for the second one 2+k-8
make it 2+k-8=0
move the k to get it alone so subtract k from both sides
2-8=-1k
-6 = -1K
you can divide by K to make K=6
plug in 2+6-8=0
0=0
X= # students who got lower grades
2x+3= # students with grade A
STEP 1:
Add the two sets above equal to 24.
x + (2x + 3)= 24
combine like terms
3x + 3= 24
subtract 3 from both sides
3x= 21
divide both sides by 3
x= 7 (# students lower than A)
STEP 2:
substitute x value from step 1 to find # grade A students
=2x + 3
=2(7) + 3
=14 + 3
=17 (# grade A students)
CHECK:
x + (2x + 3)= 24
7 + 2(7) + 3= 24
7 + 14 + 3= 24
24= 24
ANSWER: There were 17 students with grade A.
Hope this helps! :)
