How do you find two numbers whose sum is 49, if the greater number is 4 more than 8 times the smaller number?

2 Answers
Apr 5, 2017

Answer:

I got #44 and 5#

Explanation:

Call the numbers #x# and #y#, you get:
#x+y=49#
#x=8y+4#
substitute the second equation into the first:
#8y+4+y=49#
#9y=45#
#y=45/9=5#
so that:
#x=8*5+4=44#

Apr 5, 2017

Answer:

Write two equations and solve for one variable. Then substitute the value for the first variable to find the value for the second variable.

Explanation:

The first equation would be
# x + y = 49#

Where x = the first variable
Where y = the second variable.

The second equation would be

# y = 8x + 4#

where y = the larger number.

Put # 8x + 4# into the first equation in place of y this gives.

# x + 8x + 4 = 49 # solve the equation for x by combining terms

# 9x + 4 = 49# subtract 4 from both sides

# 9x + 4 - 4 = 49 -4 # this gives

# 9x = 45# Divide both sides by 9 gives

# 9x /9 = 45/9 # The answer is

# x= 5 # Now put 5 into one of the equation to find y

# y = 8(5) + 4 #

# y = 44#

To check put the values into the first equation

# 5 + 44 = 49#

x = 5 : y = 44