3. If a = + 1 and b = -2, find the value of:
(a)a² + 2ab
(b) a² + ab + 1
(c) a² – b^2+4ab (d) 3a + 56
(e) - 6a² + 5ab
(f) - 4 + 5al
Answers
Step-by-step explanation:
hope that it is useful.
Answer:
a) a² + 2ab = -3
b) a² + ab + 1=0
c) a² – b² +4ab=-11
d) 3a + 56=59
e) - 6a² + 5ab =-16
f) - 4 + 5ab = -14
Step-by-step explanation:
Given values:
a=1
b=-2
a)The question is a² + 2ab
Substitute the a and b value
a=1
b=-2
a²=1²
a²=1
a² + 2ab = 1+2(1)(-2)
==> 1+2(-2)
==> 1-4
a² + 2ab = -3
b)The question is a² + ab + 1
Substitute the a and b value
a=1
b=-2
a²=1²
a² + ab+1 = 1+(1)(-2)+1
==> 1-2+1
==> 2-2
a² + ab + 1=0
c)The question is a² – b²+4ab
Substitute the a and b value
a=1
b=-2
a²=1²
a²=1
b²=(-2)²
b²=4
a² – b² +4ab = 1-4+4(1)(-2)
==>1-4+4(-2)
==>1-4-8
==>1-12
a² – b² +4ab=-11
d)The question is 3a + 56
Substitute the a and b value
a=1
b=-2
3a + 56=3(1)+56
==>3+56=59
3a + 56=59
e)The question is - 6a² + 5ab
Substitute the a and b value
a=1
b=-2
a²=1²
a²=1
- 6a² + 5ab = -6(1)+5(1)(-2)
- 6a² + 5ab = -6+5(-2)
- 6a² + 5ab = -6-10
- 6a² + 5ab =-16
f) The question is - 4 + 5ab
Substitute the a and b value
a=1
b=-2
- 4 + 5ab =-4+5(1)(-2)
- 4 + 5ab = -4+5(-2)
- 4 + 5ab = -4-10
- 4 + 5ab = -14