QUESTION 1
Let the number be
.
If this number is decreased by 32 and the result is -58, then we can write the following equation and solve for
.
.
Group the similar terms to get;
![x=-58+32](https://tex.z-dn.net/?f=x%3D-58%2B32)
![x=-26](https://tex.z-dn.net/?f=x%3D-26)
The number is -26.
QUESTION 2
The product of 14 and
is
If the product is -28, then the require algebraic equation is
QUESTION 3
Let the number be
.
Four times this number is
.
The number increased by 78 is
.
If four times the number is the same as the number increased by 78, then we write and solve the equation;
![4y=y+78](https://tex.z-dn.net/?f=4y%3Dy%2B78)
Group the similar terms;
![4y-y=78](https://tex.z-dn.net/?f=4y-y%3D78)
Simplify
![3y=78](https://tex.z-dn.net/?f=3y%3D78)
Divide both sides by 3;
![y=\frac{78}{3}](https://tex.z-dn.net/?f=y%3D%5Cfrac%7B78%7D%7B3%7D)
![y=26](https://tex.z-dn.net/?f=y%3D26)
The number is 26
QUESTION 4
Let
represent the price of the blue bike and
represent the price of the red bike.
Then we can write the following two equations and solve simultaneously.
![b=r-14...(1)](https://tex.z-dn.net/?f=b%3Dr-14...%281%29)
![b+r=300...(2)](https://tex.z-dn.net/?f=b%2Br%3D300...%282%29)
We substitute equation (1) into equation (2) to obtain;
![r-14+r=300](https://tex.z-dn.net/?f=r-14%2Br%3D300)
Group like terms;
![r+r=300+14](https://tex.z-dn.net/?f=r%2Br%3D300%2B14)
Simplify;
![2r=314](https://tex.z-dn.net/?f=2r%3D314)
Divide both sides by 2
![r=157](https://tex.z-dn.net/?f=r%3D157)
The red bike is $157
and
The blue bike is 157-14=$143
QUESTION 5
Let
represent the age of Alex and
represent the age of his sister. Then;
![a=e+6...(1)](https://tex.z-dn.net/?f=a%3De%2B6...%281%29)
![a+e=32..(2)](https://tex.z-dn.net/?f=a%2Be%3D32..%282%29)
Put equation (1) into equation (2) to get;
![e+6+e=32](https://tex.z-dn.net/?f=e%2B6%2Be%3D32)
![\Rightarrow e+e=32-6](https://tex.z-dn.net/?f=%5CRightarrow%20e%2Be%3D32-6)
![\Rightarrow 2e=26](https://tex.z-dn.net/?f=%5CRightarrow%202e%3D26)
![\Rightarrow e=13](https://tex.z-dn.net/?f=%5CRightarrow%20e%3D13)
Alex is 13+6=19 years old.
QUESTION 6
Let
represent Mrs computer's age and
represent Mousy's age. Then;
![c=3m...(1)](https://tex.z-dn.net/?f=c%3D3m...%281%29)
![c+m=52...(2)](https://tex.z-dn.net/?f=c%2Bm%3D52...%282%29)
Put equation (1) into equation (2).
![\Rightarrow 3m+m=52](https://tex.z-dn.net/?f=%5CRightarrow%203m%2Bm%3D52)
![\Rightarrow 4m=52](https://tex.z-dn.net/?f=%5CRightarrow%204m%3D52)
![\Rightarrow m=\frac{52}{4}](https://tex.z-dn.net/?f=%5CRightarrow%20m%3D%5Cfrac%7B52%7D%7B4%7D)
![\Rightarrow m=13](https://tex.z-dn.net/?f=%5CRightarrow%20m%3D13)
Mousy is 13 years old.
QUESTION 7.
Let Mike be
years and Tom be
years.
Then;
![m=2t+5...(1)](https://tex.z-dn.net/?f=m%3D2t%2B5...%281%29)
![m+t=65...(2)](https://tex.z-dn.net/?f=m%2Bt%3D65...%282%29)
Put equation (1) into equation (2) and solve.
![\Rightarrow 2t+5+t=65](https://tex.z-dn.net/?f=%5CRightarrow%202t%2B5%2Bt%3D65)
![\Rightarrow 2t+t=65-5](https://tex.z-dn.net/?f=%5CRightarrow%202t%2Bt%3D65-5)
![\Rightarrow 3t=60](https://tex.z-dn.net/?f=%5CRightarrow%203t%3D60)
![\Rightarrow t=\frac{60}{3}](https://tex.z-dn.net/?f=%5CRightarrow%20t%3D%5Cfrac%7B60%7D%7B3%7D)
![\Rightarrow t=20](https://tex.z-dn.net/?f=%5CRightarrow%20t%3D20)
Mike is 2(20)+5=45 years old.
QUESTION 8
Let the consecutive integers be
![x,x+1,x+2](https://tex.z-dn.net/?f=x%2Cx%2B1%2Cx%2B2)
The sum of the second and third is 17 gives the equation;
![(x+1)+(x+2)=17](https://tex.z-dn.net/?f=%28x%2B1%29%2B%28x%2B2%29%3D17)
The second choice is correct
QUESTION 9
Let the consecutive integers be
![x,x+1,x+2](https://tex.z-dn.net/?f=x%2Cx%2B1%2Cx%2B2)
Their sum being 108 gives the equation
![x+x+1+x+2=108](https://tex.z-dn.net/?f=x%2Bx%2B1%2Bx%2B2%3D108)
Regroup
![x+x+x+1+2=108](https://tex.z-dn.net/?f=x%2Bx%2Bx%2B1%2B2%3D108)
Simplify the LHS
![3x+3=108](https://tex.z-dn.net/?f=3x%2B3%3D108)
Factor the LHS
![3(x+1)=108](https://tex.z-dn.net/?f=3%28x%2B1%29%3D108)
Correct choice is A
QUESTION 10
Let the two consecutive odd integers be;
![x,x+2](https://tex.z-dn.net/?f=x%2Cx%2B2)
The sum being 72 gives the equation;
![x+x+2=72](https://tex.z-dn.net/?f=x%2Bx%2B2%3D72)
Simplify the first two terms
![2x+2=72](https://tex.z-dn.net/?f=2x%2B2%3D72)