Answer: Evaluate 2x2−3x+8 when x=−4 .
Substitute −4 for x. 2(−4)2−3(−4)+8
Simplify exponents. 2(16)−3(−4)+8
Multiply. 32−(−12)+8
Subtract. 44+8
Add. 52
Now we can evaluate expressions that include multiplication and division with integers. Remember that to evaluate an expression, substitute the numbers in place of the variables, and then simplify.
Answer:
x=2 and y= -2
Step-by-step explanation:
Substitute y=x-4 in second equation
x-4=4x-10
get x terms on one side and numbers on other sides
4x-x=10-4
3x=6
divide 3 on both sides
x=2
substitute x=2 in y=x-4
y=2-4
y= -2
Answer:
Step-by-step explanation:
Solution by substitution method
3x-4y=8
and 18x-5y=10
Suppose,
3x-4y=8→(1)
and 18x-5y=10→(2)
Taking equation (1), we have
3x-4y=8
⇒3x=4y+8
⇒x=(
4y+8)/
3 →(3)
Putting x=
(4y+8
)/3 in equation (2), we get
18x-5y=10
18(
(4y+8)
/3) -5y=10
⇒24y+48-5y=10
⇒19y+48=10
⇒19y=10-48
⇒19y= -38
⇒y=-
38
/19
⇒y= -2→(4)
Now, Putting y=-2 in equation (3), we get
x=4y+8
x=
(4(-2)+8)
/3
⇒x=
(-8+8)/
3
⇒x=
0/
3
⇒x=0
∴x=0 and y= -2
