How do you solve #|7+ 7r | + 5= 40#?

2 Answers
Mar 26, 2018

Answer: #r = -6, 4#

Explanation:

#abs(7 + 7r) + 5 = 40#

#abs(7 + 7r) = 35#

# 7 + 7r = +- 35#

# 7 + 7r = + 35 => r = 28/7 = 4#

# 7 + 7r = - 35 => r = -42/7 = -6#

Mar 26, 2018

#r=-6" or "r=4#

Explanation:

#"subtract 5 from both sides"#

#rArr|7+7r|=35#

#"the expression inside the absolute value can be positive"#
#"or negative"#

#color(magenta)"Positive expression"#

#rArr7+7r=35larrcolor(blue)"subtract 7 from both sides"#

#rArr7r=28larrcolor(blue)"divide both sides by 7"#

#rArrr=4#

#color(magenta)"Negative expression"#

#-7-7r=35larrcolor(blue)"add 7 to both sides"#

#rArr-7r=42larrcolor(blue)"divide both sides by "-7#

#rArrr=-6#

#color(blue)"As a check"#

#r=4rArr|35|+5=35+5=40color(white)(x)✔︎#

#r=-6rArr|-35|+5=35+5=40color(white)(x)✔︎#

#rArrx=-6" or "x=4" are the solutions"#