Answer:
The temperature of the city a was 5 °C and b was 4 °C.
Explanation:
First we have to write the equations based on the description, this is:
![4a=8+3b\\a-2b=-3](https://img.qammunity.org/2020/formulas/mathematics/middle-school/fb7plau6t04sna2hlbmv6hv8bm9jlmavv0.png)
Now that we have the equations, we can replace the second in the first:
![4(2b-3)=8+3b](https://img.qammunity.org/2020/formulas/mathematics/middle-school/u8si504d82gj4intv112rcfbkqqv1gv8qr.png)
Now we can find the value of b:
![8b-12=8+3b](https://img.qammunity.org/2020/formulas/mathematics/middle-school/6rnr1tal27pzke115ohzhgu9u2fiotwdtl.png)
![8b-3b=8+12](https://img.qammunity.org/2020/formulas/mathematics/middle-school/xn90dr2lxmqkbf4m1g20yotyuvex7mbf15.png)
![5b=20](https://img.qammunity.org/2020/formulas/mathematics/middle-school/qxnv6nsvevna3ytbzjwmnyi6xf6juk8nvq.png)
![b=(20)/(5)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/id6j91m4p7qpthkszrfpno2d2q68g188km.png)
![b=4\\](https://img.qammunity.org/2020/formulas/mathematics/middle-school/uw92d6s8gsb4b4mq98dn92r0mg48qkm19p.png)
Now with the value of b and the second equation we can get the value of a:
![a-2(4)=-3](https://img.qammunity.org/2020/formulas/mathematics/middle-school/mqa2zy3y6h49h8aytyyqzr60ujqmo19dal.png)
![a-8=-3](https://img.qammunity.org/2020/formulas/mathematics/middle-school/1y1i2wke6mgvxr20fz4c0i1juvy1zoyyw8.png)
![a=8-3](https://img.qammunity.org/2020/formulas/mathematics/middle-school/bkf7aqy0kehv1zoe3nzy91zdvilsev6949.png)
![a=5](https://img.qammunity.org/2020/formulas/mathematics/high-school/54fdweyb8wyeue10yov59os9w11gn85p3f.png)
The temperature of the city a was 5 °C and b was 4 °C.