Answer:
1.D
2.D
3.B
4.A
5.A
Step-by-step explanation:
1.We are given that two equations
[tex]d+e=15[/tex]
[tex]-d+e=-5[/tex]
Adding two equations then we get
[tex]2 e=10[/tex]
[tex]e=\frac{10}{2}=5[/tex]
Substitute e=5 in equation one then we get
[tex]5+e=15[/tex]
[tex] d=15-5[/tex]
[tex]d=10[/tex]
Hence, the ordered pair as (10, 5).
Therefore,Option D is true.
2.We are given that two equations
Equation S:[tex]y=x+9[/tex]
Equatin T:[tex]y=2x+1[/tex]
Using substitution method
Substitute the value of y from equation one in equation second then we get
[tex]x+9=2x+1[/tex]
Therefore, option D is true.
3.We are given that two equations
Equation C :[tex]y=6x+9[/tex]
Equation D[tex]:y=6x+2[/tex]
The two equations can be written as
[tex]6x-y+9=0[/tex]
[tex]6x-y+2=0[/tex]
[tex]a_1=6,b_1=-1,c_1=9[/tex]
[tex]a_2=6,b_2=-1,c_2=2[/tex]
[tex]\frac{a_1}{a_2}=\frac{6}{6}=1:1[/tex]
[tex]\frac{b_1}{b_2}=\frac{-1}{-1}=1:1[/tex]
[tex]\frac{c_1}{c_2}=\frac{9}{2}[/tex]
[tex]\frac{a_1}{a_2}=\frac{b_1}{b_2}\neq\frac{c_1}{c_2}[/tex]
Therefore, system of equations have no solution
Hence, option B is true.
4.We are given that two equations
[tex]2x+y=-4[/tex]
[tex]y=3x+2[/tex]
Using substitution method
Substitute value of y from equation second in equation one
Then we get
[tex]2x+3x=2=-4[/tex]
[tex]5 x=-4-2[/tex]
[tex]5 x=-6[/tex]
[tex]x=-\frac{6}{5}[/tex]
Substitute the value of x in equation second then we get
[tex]y=3\times( -\frac{6}{5})+2[/tex]
[tex]y=\frac{-18+10}{5}[/tex]
[tex]y=-\frac{8}{5}[/tex]
Hence, option A is true.
5.We are given that two equations
[tex]y=-2x+1[/tex]
[tex]6x+2y=22[/tex]
Using substitution method
Substitute value of y from equation one in second equation then we get
[tex]6x+2(-2x+1)=22[/tex]
Hence, option A is true.
