A person's email for one day contained a total of 78 messages. The number of spam messages was two less than four times the number of other messages. How many of
the email messages were spam?

62 of the email messages were spam

Step-by-step explanation:

Let the number of spam and other messages be s and o respectively.

Total number of messages= 78

s +o= 78 (1)

s= 4o -2 (2)

Substitute (2) into (1):

4o -2 +o= 78

Simplify:

5o -2= 78

+2 on both sides:

5o= 78 +2

5o= 80

Divide both sides by 5:

o= 80 ÷5

o= 16

Since s +o= 78, s= 78 -o.

s= 78 -16

s= 62

solve systems of equations by graphing. a system of linear equations contains two or more equations e.g. y=0.5x+2 and y=x-2. the solution of such a system is the ordered pair that is a solution to both equations. to solve a system of linear equations graphically we graph both equations in the same coordinate system

cross multiplying, we get :

⇒ (3) × (5) = (9) × (x)

⇒ 15 = 9x