how do I find x+y, if: 5x+8y=67 and 2x-y=31. a. 98. b. 46. c. 21. d. 14. e. 7. my teacher asked me too find this but im a little confused where do i distribute and evaluate

Question

how do I find  x+y, if: 5x+8y=67 and 2x-y=31. a. 98. b. 46. c. 21. d. 14. e. 7. my teacher asked me too find this but im a little confused where do i distribute and evaluate

fwval · Answer

first we do equation 
2x - 7 = 31

rearrange to isolate 
y = 2x - 31

substitute y into 1 
5x + 8 (2x - 31) = 67

simplify
5x + 16x - 248 = 67

combine like terms
21x - 248 = 67

solve for x

add 248 both sides
21x = 315

divide by 21

x = 15

then we find y
y = 2x - 31

substitute x = 15
y = 2 (15) - 31
y = 30 - 31
y = -1

then we calculate x + y
add x and y

x + y = 15 + (-1) = 14

answer for x + y = 14 so the answer is d

fwval · Answer

is that what u needed?

TROYBOY1 · Answer

@fwval wrote:

is that what u needed?

YES! TY

fwval · Answer

@troyboy1 wrote:

@fwval wrote:

is that what u needed?

YES! TY

yw

surjithayer · Answer

5x+8y=67
2x-y=31
adding both
7x+7y=98
divide by 7
x+y=14