7 years
First of all, half of 18 is 9, and if you divide 18 by 2.5, it results in 7.2. I hope this helps!
Answer:
x = -2, y=1
Step-by-step explanation:
x-7y=-9---------------------equation 1
-x+8y=10-------------------equation 2
From equation 1, make x the subject of formula
x=7y-9----------------------equation 3
substituting x=7y-9 in equation 2,
-(7y-9)+8y=10
Expanding bracket
-7y+9+8y=10
Collecting like terms
8y-7y=10-9
y=1
substituting y=1 in 3
x=7(1)-9
x=7-9
x=-2
Step-by-step explanation:
78 = m32
m = 78/32 = 39/16 = 2.4375
104 is the answer to your problem
