# How do you solve the system #4x-y=25# and #4x+5y=-29#?

##### 2 Answers

use the elimination method to solve the simultaneous equations:

4x-y=25>eq no 1

4x+5y=-29>eq no 2

eq no 1-eq no 2

4x -y =25

(-4x-5y=29)the signs become opposite in the subtraction

0 -6y =54

-6y=54

y=54/-6

y=-9.

put the value of y=-9 into eq no 1.

(try to put the value in the equation with smaller values)

4x-(-9)=25

4x+9=25

4x=25-9

4x=16

x=16/4

x=4

S.S{4,-9}(remember that the value of the variable which comes first according to the alphabetic arrangement is always written first)

#### Explanation:

Solve by elimination and substitution

#color(blue)(4x-y=25#

#color(blue)(4x+5y=-29#

We could see that, we can eliminate

Subtract

Substitute the value of

#:.color(purple)({x,y}={-9,4}#